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    <link:label id="lab_lh_EmployeeSeveranceBenefitsRelatedRestructuringReserveAccrualAdjustment_8F78A19F13659A920727109AA06A9AD9_verboseLabel_en-US" xlink:label="lab_lh_EmployeeSeveranceBenefitsRelatedRestructuringReserveAccrualAdjustment_8F78A19F13659A920727109AA06A9AD9" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Reduction in prior employee severance benefits related restructuring accruals</link:label>
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    <link:label id="lab_us-gaap_AssetImpairmentCharges_EA3F717FC8922B8FADA2109AA06AFFB0_terseLabel_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges_EA3F717FC8922B8FADA2109AA06AFFB0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Impairment Charges</link:label>
    <link:label id="lab_us-gaap_AssetImpairmentCharges_EA3F717FC8922B8FADA2109AA06AFFB0_label_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges_EA3F717FC8922B8FADA2109AA06AFFB0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Impairment Charges</link:label>
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    <link:label id="lab_us-gaap_RestructuringReserveAccrualAdjustment1_A80E4165262CE4859844109AA06A5124_terseLabel_en-US" xlink:label="lab_us-gaap_RestructuringReserveAccrualAdjustment1_A80E4165262CE4859844109AA06A5124" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reduction in total prior restructuring accruals</link:label>
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    <link:label id="lab_us-gaap_AmortizationOfDebtDiscountPremium_E527D1B8192C3B3F756F109AA06A05DE_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfDebtDiscountPremium_E527D1B8192C3B3F756F109AA06A05DE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of Debt Discount (Premium)</link:label>
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    <link:label id="lab_lh_Specialchargewinddownofminvolumecontract_D7EB1D27B86433990DFA109AA06B6397_terseLabel_en-US" xlink:label="lab_lh_Specialchargewinddownofminvolumecontract_D7EB1D27B86433990DFA109AA06B6397" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Special charge, wind-down of min volume contract</link:label>
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    <link:label id="lab_lh_Specialchargewinddownofminvolumecontract_D7EB1D27B86433990DFA109AA06B6397_documentation_en-US" xlink:label="lab_lh_Specialchargewinddownofminvolumecontract_D7EB1D27B86433990DFA109AA06B6397" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Special charge, wind-down of min volume contract</link:label>
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    <link:label id="lab_us-gaap_PaymentsForLegalSettlements_C07D4F53F990FE6FC132109AA06C258E_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForLegalSettlements_C07D4F53F990FE6FC132109AA06C258E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payment of legal settlement</link:label>
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    <link:label id="lab_us-gaap_PostemploymentBenefitsAbstract_4899F747712A7472D354ED354E805EB9_label_en-US" xlink:label="lab_us-gaap_PostemploymentBenefitsAbstract_4899F747712A7472D354ED354E805EB9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Postemployment Benefits [Abstract]</link:label>
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    <link:label id="lab_lh_AssumedBenefitPaymentsByYearTextBlock_34114BC57DB37848E96DED354E811F31_terseLabel_en-US" xlink:label="lab_lh_AssumedBenefitPaymentsByYearTextBlock_34114BC57DB37848E96DED354E811F31" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assumed Benefit Payments By Year [Text Block]</link:label>
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    <link:label id="lab_lh_AssumedBenefitPaymentsByYearTextBlock_34114BC57DB37848E96DED354E811F31_documentation_en-US" xlink:label="lab_lh_AssumedBenefitPaymentsByYearTextBlock_34114BC57DB37848E96DED354E811F31" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">A schedule of assumed benefit payments for future periods by year. This element may be used for defined benefit, nonqualified supplemental retirement, and post-retirement benefit plans.</link:label>
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    <link:label id="lab_lh_DefinedBenefitPlanFairValueOfPlanAssetsByCategoryTableTextBlock_590C5B5C711D41E857ABED354E8193AD_terseLabel_en-US" xlink:label="lab_lh_DefinedBenefitPlanFairValueOfPlanAssetsByCategoryTableTextBlock_590C5B5C711D41E857ABED354E8193AD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan Fair Value Of Plan Assets By Category [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock_838AE3DDA7DD343A3D54ED354E82581E_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock_838AE3DDA7DD343A3D54ED354E82581E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Changes in Fair Value of Plan Assets [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_SeniorLongTermNotes_A3D54C03516E8FBF47E50CAFC78C245F_terseLabel_en-US" xlink:label="lab_us-gaap_SeniorLongTermNotes_A3D54C03516E8FBF47E50CAFC78C245F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Notes, Noncurrent</link:label>
    <link:label id="lab_us-gaap_SeniorLongTermNotes_A3D54C03516E8FBF47E50CAFC78C245F_label_en-US" xlink:label="lab_us-gaap_SeniorLongTermNotes_A3D54C03516E8FBF47E50CAFC78C245F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes, Noncurrent</link:label>
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    <link:label id="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A_terseLabel_en-US" xlink:label="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net Proceeds from Debt</link:label>
    <link:label id="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A_label_en-US" xlink:label="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Proceeds from Debt</link:label>
    <link:label id="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A_documentation_en-US" xlink:label="lab_lh_NetProceedsfromDebt_82C94417689763E7FE650CAFC793FC0A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Net Proceeds from Debt</link:label>
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    <link:label id="lab_invest_DerivativeNotionalAmount_31469F990709BD9F309A0CAFC799DEBD_label_en-US" xlink:label="lab_invest_DerivativeNotionalAmount_31469F990709BD9F309A0CAFC799DEBD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Notional Amount</link:label>
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    <link:label id="lab_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Foreign Currency Contract, Asset, Fair Value Disclosure</link:label>
    <link:label id="lab_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Currency Contract, Asset, Fair Value Disclosure</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ForeignCurrencyContractAssetFairValueDisclosure" xlink:label="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC" xlink:to="lab_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_460861C195DD55417B220CAFC7A20EFC" xlink:type="arc" />
    <link:label id="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584_terseLabel_en-US" xlink:label="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt to EBITDA (leverage) ratio</link:label>
    <link:label id="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584_label_en-US" xlink:label="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt to EBITDA (Leverage) Ratio</link:label>
    <link:label id="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584_documentation_en-US" xlink:label="lab_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt to EBITDA (Leverage) Ratio</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_DebtToEbitdaLeverageRatio" xlink:label="loc_lh_DebtToEbitdaLeverageRatio_4CC50B0D1600E07053020C3F89625584" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487_terseLabel_en-US" xlink:label="lab_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt, Current</link:label>
    <link:label id="lab_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487_label_en-US" xlink:label="lab_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtCurrent" xlink:label="loc_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487" xlink:to="lab_us-gaap_DebtCurrent_02CCBF56E39D3B76CEFD0C3F8963A487" xlink:type="arc" />
    <link:label id="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9_terseLabel_en-US" xlink:label="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal amount at maturity of zero-coupon subordinated notes outstanding</link:label>
    <link:label id="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9_label_en-US" xlink:label="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Principal amount at maturity of zero-coupon subordinated notes outstanding</link:label>
    <link:label id="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9_documentation_en-US" xlink:label="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The principal amount at maturity of zero-coupon subordinated notes outstanding at the balance sheet date.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding" xlink:label="loc_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:to="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding_980AEE81ED98524FEFFD0C3F8963F4F9" xlink:type="arc" />
    <link:label id="lab_lh_IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes_5825CEBF299BEDD0C2520C3F89634ED9_terseLabel_en-US" xlink:label="lab_lh_IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes_5825CEBF299BEDD0C2520C3F89634ED9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Issued price per principal amount at maturity</link:label>
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    <link:label id="lab_lh_IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes_5825CEBF299BEDD0C2520C3F89634ED9_documentation_en-US" xlink:label="lab_lh_IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes_5825CEBF299BEDD0C2520C3F89634ED9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The issuance price for each zero-coupon subordinated note.</link:label>
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    <link:label id="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F_terseLabel_en-US" xlink:label="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal amount of zero-coupon subordinated notes</link:label>
    <link:label id="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F_label_en-US" xlink:label="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Principal Amount Of Zero Coupon Subordinated Notes</link:label>
    <link:label id="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F_documentation_en-US" xlink:label="lab_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Principal amount of zero-coupon subordinated notes.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_PrincipalAmountOfZeroCouponSubordinatedNotes" xlink:label="loc_lh_PrincipalAmountOfZeroCouponSubordinatedNotes_BF3B80F338558720993D0C3F89634D9F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Effective Percentage</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Effective Percentage</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8" xlink:to="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_382616478496CACC49710C3F896416D8" xlink:type="arc" />
    <link:label id="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A_terseLabel_en-US" xlink:label="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock conversion rate for zero-coupon subordinated notes (per thousand)</link:label>
    <link:label id="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A_label_en-US" xlink:label="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Conversion Rate For Zero Coupon Subordinated Notes</link:label>
    <link:label id="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A_documentation_en-US" xlink:label="lab_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of shares of common stock issued for each unit of principal at maturity of zero coupon subordinated notes converted.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_StockConversionRateForZeroCouponSubordinatedNotes" xlink:label="loc_lh_StockConversionRateForZeroCouponSubordinatedNotes_83B39EEA91C27F0B14A80C3F8964FE3A" xlink:type="locator" />
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    <link:label id="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D_terseLabel_en-US" xlink:label="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum number of trading days in a period the common stock sale price must meet a specified threshold to trigger conversion price (in days)</link:label>
    <link:label id="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D_label_en-US" xlink:label="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum Number Of Trading Days To Trigger Conversion Price</link:label>
    <link:label id="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D_documentation_en-US" xlink:label="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The minimum number of trading days within a number of consecutive trading days in a quarter that the common stock price must meet a specified threshold to trigger conversion price.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_MinimumNumberOfTradingDaysToTriggerConversionPrice" xlink:label="loc_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:to="lab_lh_MinimumNumberOfTradingDaysToTriggerConversionPrice_2F4CFD5A4CDB9A5116BD0C3F8964699D" xlink:type="arc" />
    <link:label id="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744_terseLabel_en-US" xlink:label="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of consecutive trading days ending on the last trading day of the preceding quarter for the common stock sale price to reach a specified threshold to trigger conversion price (in days)</link:label>
    <link:label id="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744_label_en-US" xlink:label="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number Of Consecutive Trading Days In Quarter To Trigger Conversion Price</link:label>
    <link:label id="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744_documentation_en-US" xlink:label="lab_lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice_9DCF04A8CF2C42615E210C3F89648744" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of consecutive trading days in a quarter that the minimum number of trading days must fall within that the common stock price has met a specified threshold to trigger conversion price.</link:label>
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    <link:label id="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB_terseLabel_en-US" xlink:label="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock sales price threshold, beginning</link:label>
    <link:label id="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB_label_en-US" xlink:label="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock Sales Price Threshold Beginning</link:label>
    <link:label id="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB_documentation_en-US" xlink:label="lab_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The beginning common stock price threshold (common stock price as compared with the accreted conversion price per share of common stock), adjusted quarterly with the declining threshold percentage, that must be met within a quarter in a specified consecutive trading period to trigger conversion price.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_CommonStockSalesPriceThresholdBeginning" xlink:label="loc_lh_CommonStockSalesPriceThresholdBeginning_6EFB3CDC7C57C8CAA9D60C3F89645EAB" xlink:type="locator" />
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    <link:label id="lab_lh_CommonStockDecliningSalePriceThreshold_212FF8FB5971730487F50C3F89658903_terseLabel_en-US" xlink:label="lab_lh_CommonStockDecliningSalePriceThreshold_212FF8FB5971730487F50C3F89658903" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock sales price threshold, declining per quarter</link:label>
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    <link:label id="lab_lh_CommonStockDecliningSalePriceThreshold_212FF8FB5971730487F50C3F89658903_documentation_en-US" xlink:label="lab_lh_CommonStockDecliningSalePriceThreshold_212FF8FB5971730487F50C3F89658903" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The declining common stock sales price quarterly threshold adjustment/percentage, which thereby reduces the threshold for triggering the common stock conversion price.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_CommonStockDecliningSalePriceThreshold" xlink:label="loc_lh_CommonStockDecliningSalePriceThreshold_212FF8FB5971730487F50C3F89658903" xlink:type="locator" />
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    <link:label id="lab_lh_CommonStockSalesPriceThresholdEnding_C3384C8FB34AF05494D90C3F89650E84_documentation_en-US" xlink:label="lab_lh_CommonStockSalesPriceThresholdEnding_C3384C8FB34AF05494D90C3F89650E84" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The ending common stock price threshold (common stock price as compared with the accreted conversion price per share of common stock), adjusted quarterly with the declining threshold percentage, that must be met within a quarter in a specified consecutive trading period to trigger conversion price.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_CommonStockSalesPriceThresholdEnding" xlink:label="loc_lh_CommonStockSalesPriceThresholdEnding_C3384C8FB34AF05494D90C3F89650E84" xlink:type="locator" />
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    <link:label id="lab_lh_ZeroCouponConvertibleSubordinatedNotesConversionTriggerPrice_26084E935314406D6E800C3F8965686D_terseLabel_en-US" xlink:label="lab_lh_ZeroCouponConvertibleSubordinatedNotesConversionTriggerPrice_26084E935314406D6E800C3F8965686D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Zero Coupon Convertible Subordinated Notes Conversion Trigger Price</link:label>
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    <link:label id="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted_A426EDFF7018F017B6950C3F8965E67C_terseLabel_en-US" xlink:label="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted_A426EDFF7018F017B6950C3F8965E67C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal Amount At Maturity Of Zero Coupon Subordinated Notes Converted</link:label>
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    <link:label id="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted_A426EDFF7018F017B6950C3F8965E67C_documentation_en-US" xlink:label="lab_lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted_A426EDFF7018F017B6950C3F8965E67C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The principal amount at maturity of zero-coupon subordinated notes that were converted during the period.</link:label>
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    <link:label id="lab_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29_terseLabel_en-US" xlink:label="lab_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Value Of Cash And Common Stock In Connection With Conversions Of Zero Coupon Subordinated Notes Settled In Current Period</link:label>
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    <link:label id="lab_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29_documentation_en-US" xlink:label="lab_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The value of cash and common stock in connection with conversions of zero-coupon subordinated notes that were settled by the Company in the current period.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod" xlink:label="loc_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29" xlink:to="lab_lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod_3E22EF596BD6BFDE08D30C3F8966DD29" xlink:type="arc" />
    <link:label id="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D_terseLabel_en-US" xlink:label="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payments On Zero Coupon Subordinated Notes</link:label>
    <link:label id="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D_label_en-US" xlink:label="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments On Zero Coupon Subordinated Notes</link:label>
    <link:label id="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D_documentation_en-US" xlink:label="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_5F59730687D70BD6F1AC0C3F89663D3D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash outflow (payments) on the zero-coupon subordinated notes.</link:label>
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    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_F5BEA41F08157C7C28330C3F89664C65_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_F5BEA41F08157C7C28330C3F89664C65" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock issued upon conversion of zero-coupon subordinated notes (in shares)</link:label>
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    <link:label id="lab_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents [Member]</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsMember" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83" xlink:to="lab_us-gaap_CashAndCashEquivalentsMember_C85FE8B3BA97C06C864211940885BF83" xlink:type="arc" />
    <link:label id="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12_terseLabel_en-US" xlink:label="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. large cap - blend [Member]</link:label>
    <link:label id="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12_label_en-US" xlink:label="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Us Large Cap Blend [Member]</link:label>
    <link:label id="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12_documentation_en-US" xlink:label="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benefit plan assets invested in the U.S. large capitalization equity securities - blend category.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_UsLargeCapBlendMember" xlink:label="loc_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:to="lab_lh_UsLargeCapBlendMember_E08BA6763512A7A5E1E7119408853F12" xlink:type="arc" />
    <link:label id="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA_terseLabel_en-US" xlink:label="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. mid cap - blend [Member]</link:label>
    <link:label id="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA_label_en-US" xlink:label="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Us Mid Cap Blend [Member]</link:label>
    <link:label id="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA_documentation_en-US" xlink:label="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benefit plan assets invested in the U.S. medium capitalization equity securities - blend category.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_UsMidCapBlendMember" xlink:label="loc_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:to="lab_lh_UsMidCapBlendMember_30AFACF21B1C1000712611940886D0AA" xlink:type="arc" />
    <link:label id="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14_terseLabel_en-US" xlink:label="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. small cap - blend [Member]</link:label>
    <link:label id="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14_label_en-US" xlink:label="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Us Small Cap Blend [Member]</link:label>
    <link:label id="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14_documentation_en-US" xlink:label="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benefit plan assets invested in the U.S. small capitalization equity securities - blend category.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_UsSmallCapBlendMember" xlink:label="loc_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:to="lab_lh_UsSmallCapBlendMember_AFB4D5D1E976492E2799119408866B14" xlink:type="arc" />
    <link:label id="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7_terseLabel_en-US" xlink:label="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">International - developed [Member]</link:label>
    <link:label id="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7_label_en-US" xlink:label="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">International Developed [Member]</link:label>
    <link:label id="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7_documentation_en-US" xlink:label="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benefit plan assets invested in the international capitalization equity securities- developed category.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_InternationalDevelopedMember" xlink:label="loc_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:to="lab_lh_InternationalDevelopedMember_CE892AF939D383B4D5B71194088614E7" xlink:type="arc" />
    <link:label id="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E_terseLabel_en-US" xlink:label="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commodities index [Member]</link:label>
    <link:label id="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E_label_en-US" xlink:label="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commodities index [Member]</link:label>
    <link:label id="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E_documentation_en-US" xlink:label="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="lh-20181231.xsd#lh_CommoditiesIndexMember" xlink:label="loc_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:to="lab_lh_CommoditiesIndexMember_FE3657DD03F0F1889CCB11940887F39E" xlink:type="arc" />
    <link:label id="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE_terseLabel_en-US" xlink:label="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. fixed income [Member]</link:label>
    <link:label id="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE_label_en-US" xlink:label="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Us Fixed Income [Member]</link:label>
    <link:label id="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE_documentation_en-US" xlink:label="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benefit plan assets invested in the U.S. fixed income securities category.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_UsFixedIncomeMember" xlink:label="loc_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:to="lab_lh_UsFixedIncomeMember_DBD33449D1FD2B340B1E119408875EBE" xlink:type="arc" />
    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_C23E2AE160A8DA4AF29511940887AE02_terseLabel_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember_C23E2AE160A8DA4AF29511940887AE02" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed Income Securities [Member]</link:label>
    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_C23E2AE160A8DA4AF29511940887AE02_label_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember_C23E2AE160A8DA4AF29511940887AE02" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fixed Income Securities [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FixedIncomeSecuritiesMember" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_C23E2AE160A8DA4AF29511940887AE02" xlink:type="locator" />
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    <link:label id="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C_terseLabel_en-US" xlink:label="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mutual Funds [Member]</link:label>
    <link:label id="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C_label_en-US" xlink:label="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mutual Funds [Member]</link:label>
    <link:label id="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C_documentation_en-US" xlink:label="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mutual Funds [Member]</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_MutualFundsMember" xlink:label="loc_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:to="lab_lh_MutualFundsMember_818C5AA8CCE8F6F4FBF811940887F20C" xlink:type="arc" />
    <link:label id="lab_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9_terseLabel_en-US" xlink:label="lab_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Life and Annuity Insurance Product Line [Member]</link:label>
    <link:label id="lab_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9_label_en-US" xlink:label="lab_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Life and Annuity Insurance Product Line [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LifeAndAnnuityInsuranceProductLineMember" xlink:label="loc_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9" xlink:to="lab_us-gaap_LifeAndAnnuityInsuranceProductLineMember_1EF7F824897FAE73BF9811940887C4D9" xlink:type="arc" />
    <link:label id="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34_terseLabel_en-US" xlink:label="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans, Fair Value of Plan Assets by Category [Line Items]</link:label>
    <link:label id="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34_label_en-US" xlink:label="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan Fair Value By Asset Category Disclosure [Line Items]</link:label>
    <link:label id="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34_documentation_en-US" xlink:label="lab_lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems_13919927C275311821AF11940888FF34" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_34613CB4EB6C106D3FAA1194088966B3_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost_34613CB4EB6C106D3FAA1194088966B3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Service Cost</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_34613CB4EB6C106D3FAA1194088966B3" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4DF0A1F4460E3C33FE11119408892A0E_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4DF0A1F4460E3C33FE11119408892A0E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Amount</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4DF0A1F4460E3C33FE11119408892A0E_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4DF0A1F4460E3C33FE11119408892A0E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4DF0A1F4460E3C33FE11119408892A0E" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_D024BCBC8B566D6EE97C11940E5CCF15" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfOtherLongTermDebt_AB177C4D47E31B5CC9F311940E631E3A_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfOtherLongTermDebt_AB177C4D47E31B5CC9F311940E631E3A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Other Long-term Debt</link:label>
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    <link:label id="lab_lh_LineofCreditFacilityPayment_C06C14B973A88537B8A511940E634218_terseLabel_en-US" xlink:label="lab_lh_LineofCreditFacilityPayment_C06C14B973A88537B8A511940E634218" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility Payment</link:label>
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    <link:label id="lab_lh_LineofCreditFacilityPayment_C06C14B973A88537B8A511940E634218_documentation_en-US" xlink:label="lab_lh_LineofCreditFacilityPayment_C06C14B973A88537B8A511940E634218" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of Credit Facility Payment</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_1EC53F45EC1F9992CD9C11940E6475FC_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_1EC53F45EC1F9992CD9C11940E6475FC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from revolving credit facilities</link:label>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_1EC53F45EC1F9992CD9C11940E6475FC_label_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_1EC53F45EC1F9992CD9C11940E6475FC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Long-term Lines of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_1EC53F45EC1F9992CD9C11940E6475FC" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_9C72C2820D3A9A54FFC811940E6410FF_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_9C72C2820D3A9A54FFC811940E6410FF" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Payments on revolving credit facilities</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_9C72C2820D3A9A54FFC811940E6410FF_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_9C72C2820D3A9A54FFC811940E6410FF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Lines of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_9C72C2820D3A9A54FFC811940E6410FF" xlink:type="locator" />
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    <link:label id="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_B347647C02A20C12028A11940E6414DD_negatedLabel_en-US" xlink:label="lab_lh_PaymentsOnZeroCouponSubordinatedNotes_B347647C02A20C12028A11940E6414DD" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Payments on zero-coupon subordinated notes</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_PaymentsOnZeroCouponSubordinatedNotes" xlink:label="loc_lh_PaymentsOnZeroCouponSubordinatedNotes_B347647C02A20C12028A11940E6414DD" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsOfDebtIssuanceCosts_EA95717CB115CC01319011940E659BB6_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtIssuanceCosts_EA95717CB115CC01319011940E659BB6" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Payment of debt issuance costs</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_EA95717CB115CC01319011940E659BB6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_C6CED6B8370637532A5811940E65B1F9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_C6CED6B8370637532A5811940E65B1F9" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Capital Lease Obligations</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_C6CED6B8370637532A5811940E65B1F9_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_C6CED6B8370637532A5811940E65B1F9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Capital Lease Obligations</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:label="loc_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_C6CED6B8370637532A5811940E65B1F9" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsOfDividendsMinorityInterest_9D19D186D9B4C307078111940E65B95C_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsMinorityInterest_9D19D186D9B4C307078111940E65B95C" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Noncontrolling interest distributions</link:label>
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    <link:label id="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_C9BB3DC59B691D13C19911940E65FFBE_terseLabel_en-US" xlink:label="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_C9BB3DC59B691D13C19911940E65FFBE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net share settlement tax payments from issuance of stock to employees</link:label>
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    <link:label id="lab_lh_NetProceedsFromIssuanceOfStockToEmployees_7F3BE378449A2705FB7D11940E65268A_terseLabel_en-US" xlink:label="lab_lh_NetProceedsFromIssuanceOfStockToEmployees_7F3BE378449A2705FB7D11940E65268A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net proceeds from issuance of stock to employees</link:label>
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    <link:label id="lab_lh_NetProceedsFromIssuanceOfStockToEmployees_7F3BE378449A2705FB7D11940E65268A_documentation_en-US" xlink:label="lab_lh_NetProceedsFromIssuanceOfStockToEmployees_7F3BE378449A2705FB7D11940E65268A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash inflow associated with the amount received from holders exercising their stock options and employees related to shares purchased under the employee stock purchase plan.</link:label>
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    <link:label id="lab_lh_DeferredPaymentsOnAcquisitions_601F626EAA323A471A0311940E66EA51_documentation_en-US" xlink:label="lab_lh_DeferredPaymentsOnAcquisitions_601F626EAA323A471A0311940E66EA51" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents deferred payments (payments on accrued acquisition related liabilities) on acquisitions.</link:label>
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    <link:label id="lab_lh_Seniornotesdue2027_5E3F07D7C521027CC05906925E0CE19C_label_en-US" xlink:label="lab_lh_Seniornotesdue2027_5E3F07D7C521027CC05906925E0CE19C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior notes due 2027</link:label>
    <link:label id="lab_lh_Seniornotesdue2027_5E3F07D7C521027CC05906925E0CE19C_documentation_en-US" xlink:label="lab_lh_Seniornotesdue2027_5E3F07D7C521027CC05906925E0CE19C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior notes due 2027</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_Seniornotesdue2027" xlink:label="loc_lh_Seniornotesdue2027_5E3F07D7C521027CC05906925E0CE19C" xlink:type="locator" />
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    <link:label id="lab_lh_A3.20Seniornotesdue2022_EC788A268932BF0C284606925E0FA8D2_documentation_en-US" xlink:label="lab_lh_A3.20Seniornotesdue2022_EC788A268932BF0C284606925E0FA8D2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3.20% Senior notes due 2022</link:label>
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    <link:label id="lab_lh_A3.75Seniornotesdue2022_333F88E4C895D452631306925E0FBD5C_documentation_en-US" xlink:label="lab_lh_A3.75Seniornotesdue2022_333F88E4C895D452631306925E0FBD5C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">3.75% Senior notes due 2022</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_A3.75Seniornotesdue2022" xlink:label="loc_lh_A3.75Seniornotesdue2022_333F88E4C895D452631306925E0FBD5C" xlink:type="locator" />
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    <link:label id="lab_lh_Longtermandcapitalleaseobligationsnetofinterestcurrent_42076BE436BFCD75391F06925E1083ED_documentation_en-US" xlink:label="lab_lh_Longtermandcapitalleaseobligationsnetofinterestcurrent_42076BE436BFCD75391F06925E1083ED" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Long term and capital lease obligations, net of interest, current</link:label>
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    <link:label id="lab_lh_ProposedDamagesPerViolation_1B0330B44BE388335FE8011FC2748FD7_terseLabel_en-US" xlink:label="lab_lh_ProposedDamagesPerViolation_1B0330B44BE388335FE8011FC2748FD7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proposed damages per violation</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_C8A488B67A09C97FBADB011FC274C7D7_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_C8A488B67A09C97FBADB011FC274C7D7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Future minimum rental commitments [Abstract]</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_F2C358E16B795CB4DD03011FC2746459_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_F2C358E16B795CB4DD03011FC2746459" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2013</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_2039D90EDB7D37AC520E011FC27474D0_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_2039D90EDB7D37AC520E011FC27474D0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2014</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_ACCF23E72C4EDF6D4653011FC27405D4_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_ACCF23E72C4EDF6D4653011FC27405D4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2015</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_ACCF23E72C4EDF6D4653011FC27405D4" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_0F5641924FB15D53B36B011FC2832263_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_0F5641924FB15D53B36B011FC2832263" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2016</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_0F5641924FB15D53B36B011FC2832263" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_7652445B6304578B1BDA011FC28352A1_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_7652445B6304578B1BDA011FC28352A1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2017</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals_AE3E5F775B443C6F7350011FC2836409_negatedLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals_AE3E5F775B443C6F7350011FC2836409" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: non-cancelable sub-lease income</link:label>
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    <link:loc xlink:href="lh-20181231.xsd#lh_CashFlowLocationDomain" xlink:label="loc_lh_CashFlowLocationDomain_70159E7B5284BB525E27109B42395873" xlink:type="locator" />
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    <link:label id="lab_lh_Noncurrentassetsasreported_7F82236A4D41CE599B36109B424977E3_label_en-US" xlink:label="lab_lh_Noncurrentassetsasreported_7F82236A4D41CE599B36109B424977E3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncurrent assets, as reported</link:label>
    <link:label id="lab_lh_Noncurrentassetsasreported_7F82236A4D41CE599B36109B424977E3_documentation_en-US" xlink:label="lab_lh_Noncurrentassetsasreported_7F82236A4D41CE599B36109B424977E3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncurrent assets, as reported</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_Noncurrentassetsasreported" xlink:label="loc_lh_Noncurrentassetsasreported_7F82236A4D41CE599B36109B424977E3" xlink:type="locator" />
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    <link:loc xlink:href="lh-20181231.xsd#lh_Totalassetsasreported" xlink:label="loc_lh_Totalassetsasreported_A6D517B22CFB6ABEFF91109B42491244" xlink:type="locator" />
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    <link:label id="lab_lh_ShareholdersEquityAttributabletoParentasreported_70801665688B1E488187109B424910CE_documentation_en-US" xlink:label="lab_lh_ShareholdersEquityAttributabletoParentasreported_70801665688B1E488187109B424910CE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Shareholders Equity Attributable to Parent, as reported</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_ShareholdersEquityAttributabletoParentasreported" xlink:label="loc_lh_ShareholdersEquityAttributabletoParentasreported_70801665688B1E488187109B424910CE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockholdersEquity_FABA393B76F10C2785C5109B4249A1D3_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity_FABA393B76F10C2785C5109B4249A1D3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stockholders' Equity Attributable to Parent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_FABA393B76F10C2785C5109B4249A1D3" xlink:type="locator" />
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    <link:label id="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696_terseLabel_en-US" xlink:label="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and shareholders equity, as reported</link:label>
    <link:label id="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696_label_en-US" xlink:label="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Total liabilities and shareholders equity, as reported</link:label>
    <link:label id="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696_documentation_en-US" xlink:label="lab_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Total liabilities and shareholders equity, as reported</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_Totalliabilitiesandshareholdersequityasreported" xlink:label="loc_lh_Totalliabilitiesandshareholdersequityasreported_A1DEF12541BA55CC7150109B4249D696" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity_9A6FF75C81F954735561109B4249C7A5" xlink:type="arc" />
    <link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative, Fair Value, Net</link:label>
    <link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34_label_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Fair Value, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34" xlink:to="lab_us-gaap_DerivativeFairValueOfDerivativeNet_F34F8521F282F66705EA109B42497B34" xlink:type="arc" />
    <link:label id="lab_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Inventory, Finished Goods, Gross</link:label>
    <link:label id="lab_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968_label_en-US" xlink:label="lab_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Finished Goods, Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InventoryFinishedGoods" xlink:label="loc_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968" xlink:to="lab_us-gaap_InventoryFinishedGoods_A218C900EFCB98C5CE94109B42491968" xlink:type="arc" />
    <link:label id="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C_terseLabel_en-US" xlink:label="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership percentage below which investments are generally accounted for on the cost method (in hundredths)</link:label>
    <link:label id="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C_label_en-US" xlink:label="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cost Method Investments Maximum Ownership Percentage</link:label>
    <link:label id="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C_documentation_en-US" xlink:label="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the maximum ownership percentage of cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_CostMethodInvestmentsMaximumOwnershipPercentage" xlink:label="loc_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:to="lab_lh_CostMethodInvestmentsMaximumOwnershipPercentage_746E78CA24F70617BF3A109B4249E79C" xlink:type="arc" />
    <link:label id="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26_terseLabel_en-US" xlink:label="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable balances (gross) from Medicare and Medicaid</link:label>
    <link:label id="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26_label_en-US" xlink:label="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Accounts Receivable Medicare And Medicaid</link:label>
    <link:label id="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26_documentation_en-US" xlink:label="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gross receivable balance due from Medicare and Medicaid programs.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid" xlink:label="loc_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:to="lab_lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid_752CAE7FF9A3565465CC109B42492F26" xlink:type="arc" />
    <link:label id="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02_terseLabel_en-US" xlink:label="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated useful life of capitalized software costs (in years)</link:label>
    <link:label id="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02_label_en-US" xlink:label="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property plant and equipment useful life software average</link:label>
    <link:label id="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02_documentation_en-US" xlink:label="lab_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Capitalized software costs are amortized over the estimated useful life of the underlying system.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" xlink:label="loc_lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage_830BEA473698DB831782109B4249FC02" xlink:type="locator" />
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    <link:label id="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E_terseLabel_en-US" xlink:label="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum threshold percentage required to recognize income tax benefit (in hundredths)</link:label>
    <link:label id="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E_label_en-US" xlink:label="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Benefit Minimum Certainty Percentage</link:label>
    <link:label id="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E_documentation_en-US" xlink:label="lab_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">For tax positions that are more likely than not to be sustained on audit by the taxing authority, the entity recognizes the largest amount of tax benefit that it believes exceeds a minimum likelihood of being recognized. This element represents the minimum percentage of likelihood that a tax benefit will be realized that the entity uses to assess if a benefit should be recognized.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_IncomeTaxBenefitMinimumCertaintyPercentage" xlink:label="loc_lh_IncomeTaxBenefitMinimumCertaintyPercentage_D02EFC457E400BC6CAD8109B4249293E" xlink:type="locator" />
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    <link:label id="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641_terseLabel_en-US" xlink:label="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable from Ontario government sponsored healthcare plan</link:label>
    <link:label id="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641_label_en-US" xlink:label="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts receivable from Ontario government sponsored healthcare plan</link:label>
    <link:label id="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641_documentation_en-US" xlink:label="lab_lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan_E26D8BF08FE584266560109B42499641" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accounts receivable from Ontario government sponsored healthcare plan</link:label>
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    <link:label id="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E_terseLabel_en-US" xlink:label="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percent of gross accounts receivable due from patients</link:label>
    <link:label id="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E_label_en-US" xlink:label="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Percent of gross accounts receivable due from patients</link:label>
    <link:label id="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E_documentation_en-US" xlink:label="lab_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Percent of gross accounts receivable due from patients</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_Percentofgrossaccountsreceivableduefrompatients" xlink:label="loc_lh_Percentofgrossaccountsreceivableduefrompatients_E7DE6CE6B77463527C31109B42491D8E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther_BDA0362011CA7558E730109B4249F3DA_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther_BDA0362011CA7558E730109B4249F3DA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Current, Other</link:label>
    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther_BDA0362011CA7558E730109B4249F3DA_label_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther_BDA0362011CA7558E730109B4249F3DA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Current, Other</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther" xlink:label="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrentOther_BDA0362011CA7558E730109B4249F3DA" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_745D7ECFB1F3614974B111940901F975" xlink:type="locator" />
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    <link:label id="lab_lh_Maximumdeferralpercentageofannualbasesalary_28D766B51862467452B211940902F7FB_terseLabel_en-US" xlink:label="lab_lh_Maximumdeferralpercentageofannualbasesalary_28D766B51862467452B211940902F7FB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum deferral percentage of annual base salary</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_086BC5F128873087258F11940903EE83_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_086BC5F128873087258F11940903EE83" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Target Allocation, Percentage</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_086BC5F128873087258F11940903EE83" xlink:type="locator" />
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    <link:label id="lab_lh_NonElectiveContribution_F8208EA82571CD6202BE11940903AE99_label_en-US" xlink:label="lab_lh_NonElectiveContribution_F8208EA82571CD6202BE11940903AE99" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non Elective Contribution</link:label>
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    <link:loc xlink:href="lh-20181231.xsd#lh_NonElectiveContribution" xlink:label="loc_lh_NonElectiveContribution_F8208EA82571CD6202BE11940903AE99" xlink:type="locator" />
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    <link:label id="lab_lh_DiscretionaryContributionPercentageMinimum_1A36AE7ADE3378D4DA1311940903AC8C_label_en-US" xlink:label="lab_lh_DiscretionaryContributionPercentageMinimum_1A36AE7ADE3378D4DA1311940903AC8C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discretionary Contribution Percentage Minimum</link:label>
    <link:label id="lab_lh_DiscretionaryContributionPercentageMinimum_1A36AE7ADE3378D4DA1311940903AC8C_documentation_en-US" xlink:label="lab_lh_DiscretionaryContributionPercentageMinimum_1A36AE7ADE3378D4DA1311940903AC8C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Discretionary contribution percentage by the company for eligible employees based on service, range minimum.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_DiscretionaryContributionPercentageMinimum" xlink:label="loc_lh_DiscretionaryContributionPercentageMinimum_1A36AE7ADE3378D4DA1311940903AC8C" xlink:type="locator" />
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    <link:label id="lab_lh_DiscretionaryContributionPercentageMaximum_D6ABCDC2901BC0323366119409033142_label_en-US" xlink:label="lab_lh_DiscretionaryContributionPercentageMaximum_D6ABCDC2901BC0323366119409033142" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discretionary Contribution Percentage Maximum</link:label>
    <link:label id="lab_lh_DiscretionaryContributionPercentageMaximum_D6ABCDC2901BC0323366119409033142_documentation_en-US" xlink:label="lab_lh_DiscretionaryContributionPercentageMaximum_D6ABCDC2901BC0323366119409033142" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The maximum discretionary contribution % by the company for eligible employees based on service.</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_EE932415518EEB6A3C59011FE424379F_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet_EE932415518EEB6A3C59011FE424379F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income taxes, net of refunds</link:label>
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    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_85BE5A858F2737B13415E2CB54E51242_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_85BE5A858F2737B13415E2CB54E51242" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average remaining contractual term of options outstanding (in years)</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_9B2CC441BA1E22F19BFBE2CB54E5BEB4_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_9B2CC441BA1E22F19BFBE2CB54E5BEB4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value of options outstanding</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_BF8703EB154C16DC643CE2CB54E6D82B_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_BF8703EB154C16DC643CE2CB54E6D82B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of options vested and expected to vest</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_B5972C7E901EA1CDF3D8E2CB54E719C1_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_B5972C7E901EA1CDF3D8E2CB54E719C1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average exercise price per option, vested and expected to vest options</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_B5972C7E901EA1CDF3D8E2CB54E719C1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_B5972C7E901EA1CDF3D8E2CB54E719C1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice_7A3E47E42E957A4B3E13E2CB54E7BBD2_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice_7A3E47E42E957A4B3E13E2CB54E7BBD2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average exercise price per exercisable option</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_BBF25406635454264DA9E2CB54E79F09_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_BBF25406635454264DA9E2CB54E79F09" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value, vested and expected to vest options</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_8ACA4F4C20B4AA2A25C7E2CB54E7B557_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_8ACA4F4C20B4AA2A25C7E2CB54E7B557" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of options exercisable</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanFairValueEmployeePurchaseRight_ABE3F628BD52525B0BF4E2CB54F85816_terseLabel_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanFairValueEmployeePurchaseRight_ABE3F628BD52525B0BF4E2CB54F85816" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of the employee's purchase right</link:label>
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    <link:label id="lab_lh_RestrictedStockPerformanceSharesExpense_BCFC8B7AAAB839ED20C2E2CB55074304_terseLabel_en-US" xlink:label="lab_lh_RestrictedStockPerformanceSharesExpense_BCFC8B7AAAB839ED20C2E2CB55074304" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted stock and performance share compensation expense</link:label>
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    <link:label id="lab_lh_RestrictedStockPerformanceSharesExpense_BCFC8B7AAAB839ED20C2E2CB55074304_documentation_en-US" xlink:label="lab_lh_RestrictedStockPerformanceSharesExpense_BCFC8B7AAAB839ED20C2E2CB55074304" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The noncash expense that represents the cost of restricted stock and performance shares distributed to employees as compensation.</link:label>
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    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_34719722A927B8A931E8E2CB5507E429_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_34719722A927B8A931E8E2CB5507E429" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrecognized compensation cost related to nonvested restricted stock and performance share-based compensation arrangements</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanDisclosureAbstract_CA65800DCAD120BC198CE2CB5507469F_terseLabel_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanDisclosureAbstract_CA65800DCAD120BC198CE2CB5507469F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employee Stock Purchase Plan Disclosure</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanNumberOfAuthorizedShares_5A4C9FF8E9962C73DCB1E2CB55071911_terseLabel_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanNumberOfAuthorizedShares_5A4C9FF8E9962C73DCB1E2CB55071911" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shares of common stock authorized for issuance under the employee stock purchase plan</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanNumberOfAuthorizedShares_5A4C9FF8E9962C73DCB1E2CB55071911_documentation_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanNumberOfAuthorizedShares_5A4C9FF8E9962C73DCB1E2CB55071911" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The maximum number of shares originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for purchase under the employee stock purchase plan.</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA_terseLabel_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">The employee stock purchase plan permits employees to purchase shares of common stock at a certain percentage of the market price (in hundredths)</link:label>
    <link:label id="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA_label_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employee Stock Purchase Plan Percent Of Market Price</link:label>
    <link:label id="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA_documentation_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanPercentOfMarketPrice_599281C7BF9C4C7F949CE2CB550733FA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The percentage of the market price of common stock participating employees are able to purchase company stock.</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanNumberOfSharesPurchased_A215C16CE7813A94684AE2CB5507DFA4_terseLabel_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanNumberOfSharesPurchased_A215C16CE7813A94684AE2CB5507DFA4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of shares purchased by eligible employees</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanNumberOfSharesPurchased_A215C16CE7813A94684AE2CB5507DFA4_documentation_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanNumberOfSharesPurchased_A215C16CE7813A94684AE2CB5507DFA4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of shares under the employee stock purchase plan purchased by eligible employees during the period.</link:label>
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    <link:label id="lab_lh_EmployeeStockPurchasePlanExpense_822D693C01372667F385E2CB5507EA1F_documentation_en-US" xlink:label="lab_lh_EmployeeStockPurchasePlanExpense_822D693C01372667F385E2CB5507EA1F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The expense amount recognized during the period related to the Company's employee stock purchase plan.</link:label>
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    <link:label id="lab_us-gaap_QuarterlyFinancialDataAbstract_18F706ED215C127C0EDDE3246AA6DEB5_terseLabel_en-US" xlink:label="lab_us-gaap_QuarterlyFinancialDataAbstract_18F706ED215C127C0EDDE3246AA6DEB5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of unaudited quarterly data</link:label>
    <link:label id="lab_us-gaap_QuarterlyFinancialDataAbstract_18F706ED215C127C0EDDE3246AA6DEB5_label_en-US" xlink:label="lab_us-gaap_QuarterlyFinancialDataAbstract_18F706ED215C127C0EDDE3246AA6DEB5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Quarterly Financial Data [Abstract]</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareAbstract_670477A2260A34B9D7CCE3246AA88A0F_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract_670477A2260A34B9D7CCE3246AA88A0F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Earnings Per Share</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_670477A2260A34B9D7CCE3246AA88A0F_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract_670477A2260A34B9D7CCE3246AA88A0F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareBasic_31510A30DBC80A0DFC9EE3246AA9C121_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic_31510A30DBC80A0DFC9EE3246AA9C121" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Basic earnings per share (in dollars per share)</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareDiluted_2998FAED0B1EE06B6188E3246AA97670_netLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted_2998FAED0B1EE06B6188E3246AA97670" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Diluted earnings per common share (in dollars per share)</link:label>
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    <link:label id="lab_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_459330636D1C0B42A3D4E2B84E382F16_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_459330636D1C0B42A3D4E2B84E382F16" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset</link:label>
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Future Amortization Expense</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_D369886828C5468F0D41E2B84E38AC5C" xlink:type="arc" />
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated amortization expense, 2013</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_A635715106E295DDE7E0E2B84E38B706" xlink:type="arc" />
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_4870AA45489E2C942853E2B84E39F995_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_4870AA45489E2C942853E2B84E39F995" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated amortization expense, 2014</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_6BE8415C4E268CB38013ED354C4C492A_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_6BE8415C4E268CB38013ED354C4C492A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_6BE8415C4E268CB38013ED354C4C492A" xlink:type="locator" />
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    <link:label id="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861_terseLabel_en-US" xlink:label="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized Software Costs</link:label>
    <link:label id="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861_label_en-US" xlink:label="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Internal Use Software [Policy Text Block]</link:label>
    <link:label id="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861_documentation_en-US" xlink:label="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Describes an entity's accounting policy for costs incurred when both (1) the software is acquired, internally developed, or modified solely to meet the entity's internal needs, and (2) during the software's development or modification, no substantive plan exists or is being developed to market the software externally.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_InternalUseSoftwarePolicyTextBlock" xlink:label="loc_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:to="lab_lh_InternalUseSoftwarePolicyTextBlock_87F0EBD0C47516435301ED354C4D4861" xlink:type="arc" />
    <link:label id="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60_terseLabel_en-US" xlink:label="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Lived Assets</link:label>
    <link:label id="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60_label_en-US" xlink:label="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long Lived Assets [Policy Text Block]</link:label>
    <link:label id="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60_documentation_en-US" xlink:label="lab_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Describes an entity's impairment evaluation policy for long-lived assets. This policy addresses impairment of goodwill and long-lived assets.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_LongLivedAssetsPolicyTextBlock" xlink:label="loc_lh_LongLivedAssetsPolicyTextBlock_3464193E9598EA70BCD9ED354C4DDA60" xlink:type="locator" />
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    <link:label id="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8_terseLabel_en-US" xlink:label="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intangible Assets</link:label>
    <link:label id="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8_label_en-US" xlink:label="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets Finite Lived [Policy Text Block]</link:label>
    <link:label id="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8_documentation_en-US" xlink:label="lab_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Describes an entity's accounting policy for finite-lived intangible assets. This accounting policy also may address: (1) the amortization method used (2) the useful lives of such assets (3) how the entity assesses and measures impairment of such assets.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_IntangibleAssetsFiniteLivedPolicyTextBlock" xlink:label="loc_lh_IntangibleAssetsFiniteLivedPolicyTextBlock_8F17B5B37EDC154A86FDED354C4DCDB8" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtPolicyTextBlock_6ED057A50AF4F998C6D4ED354C4EEE0F_terseLabel_en-US" xlink:label="lab_us-gaap_DebtPolicyTextBlock_6ED057A50AF4F998C6D4ED354C4EEE0F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtPolicyTextBlock" xlink:label="loc_us-gaap_DebtPolicyTextBlock_6ED057A50AF4F998C6D4ED354C4EEE0F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtPolicyTextBlock_6ED057A50AF4F998C6D4ED354C4EEE0F" xlink:to="lab_us-gaap_DebtPolicyTextBlock_6ED057A50AF4F998C6D4ED354C4EEE0F" xlink:type="arc" />
    <link:label id="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F_terseLabel_en-US" xlink:label="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Professional Liability</link:label>
    <link:label id="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F_label_en-US" xlink:label="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Professional Liability [Policy Text Block]</link:label>
    <link:label id="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F_documentation_en-US" xlink:label="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Describes an entity's accounting policy for self-insurance of professional liability claims, which may include policies for calculating a liability amount.</link:label>
    <link:loc xlink:href="lh-20181231.xsd#lh_ProfessionalLiabilityPolicyTextBlock" xlink:label="loc_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:to="lab_lh_ProfessionalLiabilityPolicyTextBlock_3B7E5FF56228EAF740A3ED354C4EA22F" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="loc_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B" xlink:to="lab_us-gaap_IncomeTaxPolicyTextBlock_71D4CA0E5A28DF81B3F3ED354C4EB32B" xlink:type="arc" />
    <link:label id="lab_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Financial Instruments</link:label>
    <link:label id="lab_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6_label_en-US" xlink:label="lab_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivatives, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativesPolicyTextBlock" xlink:label="loc_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6" xlink:to="lab_us-gaap_DerivativesPolicyTextBlock_7E1C5A86085AC2C2B54CED354C4E18B6" xlink:type="arc" />
    <link:label id="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value of Financial Instruments</link:label>
    <link:label id="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8_label_en-US" xlink:label="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value of Financial Instruments, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:label="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8" xlink:to="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_6C1DDAAF04E260783D30ED354C4E02A8" xlink:type="arc" />
    <link:label id="lab_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB_terseLabel_en-US" xlink:label="lab_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Research and Development</link:label>
    <link:label id="lab_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB_label_en-US" xlink:label="lab_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Research and Development Expense, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB" xlink:to="lab_us-gaap_ResearchAndDevelopmentExpensePolicy_163D84C9530C3C183442ED354C4E65CB" xlink:type="arc" />
    <link:label id="lab_us-gaap_ForeignCurrencyDisclosureTextBlock_A50C3649A99FDDE6A901ED354C4F6F14_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyDisclosureTextBlock_A50C3649A99FDDE6A901ED354C4F6F14" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign Currency Disclosure [Text Block]</link:label>
    <link:label id="lab_us-gaap_ForeignCurrencyDisclosureTextBlock_A50C3649A99FDDE6A901ED354C4F6F14_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyDisclosureTextBlock_A50C3649A99FDDE6A901ED354C4F6F14" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Currency Disclosure [Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ForeignCurrencyDisclosureTextBlock" xlink:label="loc_us-gaap_ForeignCurrencyDisclosureTextBlock_A50C3649A99FDDE6A901ED354C4F6F14" xlink:type="locator" />
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    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_CBCDECE088E6DE7F536D07033695B900_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_CBCDECE088E6DE7F536D07033695B900" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Population of Financial Assets and Liabilities Subject to Fair Value Measurements [Table]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_CBCDECE088E6DE7F536D07033695B900" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_CBCDECE088E6DE7F536D07033695B900" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_CBCDECE088E6DE7F536D07033695B900" xlink:type="arc" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_4E7C8034ABF2807A2E50070336A5B6F0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_4E7C8034ABF2807A2E50070336A5B6F0" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_4E7C8034ABF2807A2E50070336A5B6F0" xlink:type="arc" />
    <link:label id="lab_lh_IncreaseDecreaseInNoncontrollingInterestPut_E7916A168E8506FCD6A7070336A539D1_terseLabel_en-US" xlink:label="lab_lh_IncreaseDecreaseInNoncontrollingInterestPut_E7916A168E8506FCD6A7070336A539D1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Noncontrolling Interest Put</link:label>
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