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  <xsd:element id="lh_AdditionalSharesAuthorizedwithAcquisition" name="AdditionalSharesAuthorizedwithAcquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_AdjustmentsToAdditionalPaidInCapitalTaxEffectAssociatedWithOptionExercisesFromStockPlans" name="AdjustmentsToAdditionalPaidInCapitalTaxEffectAssociatedWithOptionExercisesFromStockPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_AlbertaCanadaMember" name="AlbertaCanadaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_AmountOutstandingLettersOfCredit" name="AmountOutstandingLettersOfCredit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_AssumedBenefitPaymentsByYearTextBlock" name="AssumedBenefitPaymentsByYearTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_AssumptionsUsedToDevelopFairValueEstimatesAbstract" name="AssumptionsUsedToDevelopFairValueEstimatesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Benefitspaidforanunfundedbenefitplan" name="Benefitspaidforanunfundedbenefitplan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_BridgeTermCreditFacilityAgreementMaximumBorrowingAmount" name="BridgeTermCreditFacilityAgreementMaximumBorrowingAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_CanadianLicensesAlbertaCanada" name="CanadianLicensesAlbertaCanada" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_Capitalleaseobligationsnetofinterest" name="Capitalleaseobligationsnetofinterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_Capitalleaseobligationsnetofinterestcurrent" name="Capitalleaseobligationsnetofinterestcurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_CapitationRevenuePercentage" name="CapitationRevenuePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CashPaidDuringPeriodForAbstract" name="CashPaidDuringPeriodForAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CashonHandUsedforAcquisition" name="CashonHandUsedforAcquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_Cashpaidforacquisition" name="Cashpaidforacquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_Changeincontrolandseverancepayments" name="Changeincontrolandseverancepayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_ChangesInCommonSharesIssuedAndHeldInTreasuryTableTextBlock" name="ChangesInCommonSharesIssuedAndHeldInTreasuryTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ChangesInOptionsOutstandingUnderStockIncentivePlansAdditionalDisclosuresAbstract" name="ChangesInOptionsOutstandingUnderStockIncentivePlansAdditionalDisclosuresAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CharlotteNorthCarolinaMember" name="CharlotteNorthCarolinaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ClinicaldiagnosticslaboratoryMember" name="ClinicaldiagnosticslaboratoryMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Codefendantsapportionedresponsibility" name="Codefendantsapportionedresponsibility" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CommoditiesIndexMember" name="CommoditiesIndexMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CommonSharesHeldInTreasuryRollforwardAbstract" name="CommonSharesHeldInTreasuryRollforwardAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CommonSharesIssuedAndOutstandingAbstract" name="CommonSharesIssuedAndOutstandingAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CommonSharesIssuedRollforwardAbstract" name="CommonSharesIssuedRollforwardAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CommonStockDecliningSalePriceThreshold" name="CommonStockDecliningSalePriceThreshold" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CommonStockRepurchaseAuthorizationOutstanding" name="CommonStockRepurchaseAuthorizationOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_CommonStockSalesPriceThresholdBeginning" name="CommonStockSalesPriceThresholdBeginning" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CommonStockSalesPriceThresholdEnding" name="CommonStockSalesPriceThresholdEnding" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CommonsStockIssuedDuringPeriodSharesEmployeeStockPlans" name="CommonsStockIssuedDuringPeriodSharesEmployeeStockPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CommonstocksharesissuedforAcquisition" name="CommonstocksharesissuedforAcquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Companysapportionedresponsibility" name="Companysapportionedresponsibility" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ConcentrationOfCreditRiskPolicyTextBlock" name="ConcentrationOfCreditRiskPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ConcentrationRiskAccountsReceivableMedicareAndMedicaid" name="ConcentrationRiskAccountsReceivableMedicareAndMedicaid" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_ConsolidatedStatementsofOperationsAbstract" name="ConsolidatedStatementsofOperationsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ContingentCashInterestAccrualRate" name="ContingentCashInterestAccrualRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ContingentCashInterestAccrualRateDescription" name="ContingentCashInterestAccrualRateDescription" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ContingentCashInterestAccrualRatePeriod" name="ContingentCashInterestAccrualRatePeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ContractuallyDeterminedValueMember" name="ContractuallyDeterminedValueMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ConversionOfZeroCouponConvertibleDebt" name="ConversionOfZeroCouponConvertibleDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_CostMethodInvestmentsMaximumOwnershipPercentage" name="CostMethodInvestmentsMaximumOwnershipPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CovanceDrugDevelopmentMember" name="CovanceDrugDevelopmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CovanceInc.Member" name="CovanceInc.Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_CovanceMember" name="CovanceMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Covanceseniornotesdue2020Domain" name="Covanceseniornotesdue2020Domain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_CreditFacilityMaximumLettersofCredit" name="CreditFacilityMaximumLettersofCredit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_CreditFacilityMaximumSwingLineBorrowings" name="CreditFacilityMaximumSwingLineBorrowings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_CreditFacilityOptiontoIncrease" name="CreditFacilityOptiontoIncrease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_DebtConversionDateOfSubordinatedNotesAndIndenture" name="DebtConversionDateOfSubordinatedNotesAndIndenture" nillable="true" substitutionGroup="xbrli:item" type="xbrli:dateItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DebtCovenantActualMember" name="DebtCovenantActualMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DebtCovenantRequirementForNumberOfConsecutiveFiscalQuarters" name="DebtCovenantRequirementForNumberOfConsecutiveFiscalQuarters" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DebtCovenantRequirementMember" name="DebtCovenantRequirementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DebtToEbitdaLeverageRatio" name="DebtToEbitdaLeverageRatio" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_DeferredIncomeTaxesAndOtherTaxLiabilities" name="DeferredIncomeTaxesAndOtherTaxLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_DeferredPaymentsOnAcquisitions" name="DeferredPaymentsOnAcquisitions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DeferredtaxliabilityDomain" name="DeferredtaxliabilityDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanActualAssetAllocation" name="DefinedBenefitPlanActualAssetAllocation" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_DefinedBenefitPlanAmortizationAndDeferral" name="DefinedBenefitPlanAmortizationAndDeferral" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanAssumptionsUsedExpectedLongTermReturnOnAssets" name="DefinedBenefitPlanAssumptionsUsedExpectedLongTermReturnOnAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_DefinedBenefitPlanDisclosureEstimatedFutureBenefitsPaymentsLineItems" name="DefinedBenefitPlanDisclosureEstimatedFutureBenefitsPaymentsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanExpectedRateOfReturnOnAssetsEquitySecurities" name="DefinedBenefitPlanExpectedRateOfReturnOnAssetsEquitySecurities" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanExpectedRateOfReturnOnAssetsFixedIncomeSecurities" name="DefinedBenefitPlanExpectedRateOfReturnOnAssetsFixedIncomeSecurities" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanExpectedRateOfReturnOnAssetsOtherAssets" name="DefinedBenefitPlanExpectedRateOfReturnOnAssetsOtherAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanExpectedSalaryIncrease" name="DefinedBenefitPlanExpectedSalaryIncrease" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems" name="DefinedBenefitPlanFairValueByAssetCategoryDisclosureLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DefinedBenefitPlanFairValueOfPlanAssetsByCategoryTableTextBlock" name="DefinedBenefitPlanFairValueOfPlanAssetsByCategoryTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DepreciationAndAmortizationOfLeasedAssets" name="DepreciationAndAmortizationOfLeasedAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_DepreciationandAmortizationofIntangibleAssets" name="DepreciationandAmortizationofIntangibleAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DisclosureOfShareBasedCompensationArrangementsStockOptionsExercisedAbstract" name="DisclosureOfShareBasedCompensationArrangementsStockOptionsExercisedAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DisclosureOfShareBasedCompensationArrangementsStockOptionsExercisedTableTextBlock" name="DisclosureOfShareBasedCompensationArrangementsStockOptionsExercisedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DiscretionaryContributionPercentageMaximum" name="DiscretionaryContributionPercentageMaximum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_DiscretionaryContributionPercentageMinimum" name="DiscretionaryContributionPercentageMinimum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_EffectOnOperationsForBothCompanyPlanAndPepAbstract" name="EffectOnOperationsForBothCompanyPlanAndPepAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_EmployeeSeveranceBenefitsRelatedRestructuringReserveAccrualAdjustment" name="EmployeeSeveranceBenefitsRelatedRestructuringReserveAccrualAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_EmployeeStockPurchasePlanDisclosureAbstract" name="EmployeeStockPurchasePlanDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_EmployeeStockPurchasePlanExpense" name="EmployeeStockPurchasePlanExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_EmployeeStockPurchasePlanFairValueEmployeePurchaseRight" name="EmployeeStockPurchasePlanFairValueEmployeePurchaseRight" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_EmployeeStockPurchasePlanNumberOfAuthorizedShares" name="EmployeeStockPurchasePlanNumberOfAuthorizedShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_EmployeeStockPurchasePlanNumberOfSharesPurchased" name="EmployeeStockPurchasePlanNumberOfSharesPurchased" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_EmployeeStockPurchasePlanPercentOfMarketPrice" name="EmployeeStockPurchasePlanPercentOfMarketPrice" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Employertaxesonacceleratedequity" name="Employertaxesonacceleratedequity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ExcludingCovanceMember" name="ExcludingCovanceMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ExcludingTermLoanCommitmentMember" name="ExcludingTermLoanCommitmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ExcludingUnderwritingDiscountsOtherFeesMember" name="ExcludingUnderwritingDiscountsOtherFeesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_FacilityRelatedRestructuringReserveAccrualAdjustment" name="FacilityRelatedRestructuringReserveAccrualAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_FairValueLiabilitiesMeasuredOnRecurringBasisDeferredCompensationLiability" name="FairValueLiabilitiesMeasuredOnRecurringBasisDeferredCompensationLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_FairValueLiabilitiesMeasuredOnRecurringBasisNoncontrollingInterestPuts" name="FairValueLiabilitiesMeasuredOnRecurringBasisNoncontrollingInterestPuts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_FairValuesOptionsAndPurchaseRightAbstract" name="FairValuesOptionsAndPurchaseRightAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_FederalTaxLossCarryovers" name="FederalTaxLossCarryovers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_FederalTaxLossCarryoversExpirationDates" name="FederalTaxLossCarryoversExpirationDates" nillable="true" substitutionGroup="xbrli:item" type="xbrli:dateItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_FlorenceSouthCarolinaMember" name="FlorenceSouthCarolinaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ForeignCurrencyTranslationMember" name="ForeignCurrencyTranslationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ForeignTaxLossCarryovers" name="ForeignTaxLossCarryovers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_ForeignTaxLossCarryoverwithValuationAllowance" name="ForeignTaxLossCarryoverwithValuationAllowance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_GenomicAndEsotericTestingMember" name="GenomicAndEsotericTestingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_IncomeAbstract" name="IncomeAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterestAbstract" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterestAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IncomeTaxBenefitMinimumCertaintyPercentage" name="IncomeTaxBenefitMinimumCertaintyPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_IncreaseDecreaseInNoncontrollingInterestPut" name="IncreaseDecreaseInNoncontrollingInterestPut" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_IncreaseDecreaseinNoncontrollingInterestPutAxis" name="IncreaseDecreaseinNoncontrollingInterestPutAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_IncreaseDecreaseinNoncontrollingInterestPutDomain" name="IncreaseDecreaseinNoncontrollingInterestPutDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IncrementalCommonSharesAttributableToRestrictedStockAwardsAndOther" name="IncrementalCommonSharesAttributableToRestrictedStockAwardsAndOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IncrementalCommonSharesAttributableToStockOptions" name="IncrementalCommonSharesAttributableToStockOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
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  <xsd:element id="lh_InterestPaidInCash" name="InterestPaidInCash" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_InternalUseSoftwarePolicyTextBlock" name="InternalUseSoftwarePolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_InternationalDevelopedMember" name="InternationalDevelopedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IssuanceOfCommonStockUnderEmployeeStockPlans" name="IssuanceOfCommonStockUnderEmployeeStockPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_Issuanceofcommonstockforacquisitionconsideration" name="Issuanceofcommonstockforacquisitionconsideration" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes" name="IssuedPriceFromIssuanceOfZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_LabCorpDiagnosticsMember" name="LabCorpDiagnosticsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_LaboratoriesAndRelatedAssetsMember" name="LaboratoriesAndRelatedAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_LineofCreditFacilityPayment" name="LineofCreditFacilityPayment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_LipoScienceMember" name="LipoScienceMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element id="lh_Longtermandcapitalleasefutureminimumpaymentsinterestincludedinpayments" name="Longtermandcapitalleasefutureminimumpaymentsinterestincludedinpayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_Longtermandcapitalleaseobligationsnetofinterest" name="Longtermandcapitalleaseobligationsnetofinterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
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  <xsd:element id="lh_Longtermdebtfutureminimumpaymentsinterestincludedinpayments" name="Longtermdebtfutureminimumpaymentsinterestincludedinpayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_LossContingencyDamagesAwardedGross" name="LossContingencyDamagesAwardedGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
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  <xsd:element id="lh_Maximumdeferralpercentageofannualbasesalary" name="Maximumdeferralpercentageofannualbasesalary" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Maximumdeferralpercentageofannualcashincentivepay" name="Maximumdeferralpercentageofannualcashincentivepay" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_MedicareMedicaidRevenuePercentage" name="MedicareMedicaidRevenuePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_MinimumNumberOfTradingDaysToTriggerConversionPrice" name="MinimumNumberOfTradingDaysToTriggerConversionPrice" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_MinimumPercentageMarketToCalculatedPriceAtWhichContingentCashInterestIsDue" name="MinimumPercentageMarketToCalculatedPriceAtWhichContingentCashInterestIsDue" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_MutualFundsMember" name="MutualFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_NetDefinedBenefitPlanAmortizationAndDeferral" name="NetDefinedBenefitPlanAmortizationAndDeferral" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NetProceedsFromIssuanceOfStockToEmployees" name="NetProceedsFromIssuanceOfStockToEmployees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NetProceedsfromDebt" name="NetProceedsfromDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_NetRestructuringAndOtherSpecialCharges" name="NetRestructuringAndOtherSpecialCharges" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
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  <xsd:element id="lh_NonElectiveContribution" name="NonElectiveContribution" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Noncashconsideration" name="Noncashconsideration" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
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  <xsd:element id="lh_NoncontrollingInterestMezzanineEquity" name="NoncontrollingInterestMezzanineEquity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_Note14StockCompensationPlanAbstract" name="Note14StockCompensationPlanAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Notespayableandotherexcludingcurrentmaturities" name="Notespayableandotherexcludingcurrentmaturities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice" name="NumberOfConsecutiveTradingDaysInQuarterToTriggerConversionPrice" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_NumberOfDaysUsedToEstablishAverageMarketPriceOfZeroCouponSubordinatedNotes" name="NumberOfDaysUsedToEstablishAverageMarketPriceOfZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:normalizedStringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_NumberOfPutativeClassActions" name="NumberOfPutativeClassActions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_NumberOfRecipients" name="NumberOfRecipients" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_Numberofyearsrestructuringliabilitiesexpectedtobepaidoutover" name="Numberofyearsrestructuringliabilitiesexpectedtobepaidoutover" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_OperatingLeasesFutureMinimumPaymentsDueIncludedInRestructuringAndAcquisitionAccruals" name="OperatingLeasesFutureMinimumPaymentsDueIncludedInRestructuringAndAcquisitionAccruals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_OperatingLeasesFutureMinimumPaymentsDueLessRestructuringAcquisitionAccrualsAndFutureMinimumSubleaseRentals" name="OperatingLeasesFutureMinimumPaymentsDueLessRestructuringAcquisitionAccrualsAndFutureMinimumSubleaseRentals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_OtherLiabilitiesNoncurrentOther" name="OtherLiabilitiesNoncurrentOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_OtherSpecialCharges" name="OtherSpecialCharges" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_OthercountriesMember" name="OthercountriesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Otherspecialchargedissolutionofequityinvestment" name="Otherspecialchargedissolutionofequityinvestment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_Otherspecialchargesnoncapitalizedcosts" name="Otherspecialchargesnoncapitalizedcosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_OutstandingStockRepurchaseAuthorizationAbstract" name="OutstandingStockRepurchaseAuthorizationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_PatentsLicensesAndTechnologyMember" name="PatentsLicensesAndTechnologyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_PaymentreductionbyAssemblyBillNo.1494" name="PaymentreductionbyAssemblyBillNo.1494" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_PaymentreductionbyAssemblyBillNo.97" name="PaymentreductionbyAssemblyBillNo.97" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_PaymentsOnZeroCouponSubordinatedNotes" name="PaymentsOnZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_Paymentsonbridgeloan" name="Paymentsonbridgeloan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_PerShareAmountAbstract" name="PerShareAmountAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_PercentofRevenueContributed" name="PercentofRevenueContributed" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Percentofgrossaccountsreceivableduefrompatients" name="Percentofgrossaccountsreceivableduefrompatients" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_Percentoflowestmaximumcaponpayments" name="Percentoflowestmaximumcaponpayments" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Postcombinationaccelerationofstockcompensationexpense" name="Postcombinationaccelerationofstockcompensationexpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_PreviouslyRecordedLitigationReserveInConnectionWithFalseClaimsActLawsuit" name="PreviouslyRecordedLitigationReserveInConnectionWithFalseClaimsActLawsuit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted" name="PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesConverted" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding" name="PrincipalAmountAtMaturityOfZeroCouponSubordinatedNotesOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_PrincipalAmountOfZeroCouponSubordinatedNotes" name="PrincipalAmountOfZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_Proceedsfrombridgeloan" name="Proceedsfrombridgeloan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_ProfessionalLiabilityPolicyTextBlock" name="ProfessionalLiabilityPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Proformaconsolidateddilutedearningspershare" name="Proformaconsolidateddilutedearningspershare" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Proformaconsolidatednetincome" name="Proformaconsolidatednetincome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_Proformaconsolidatednetrevenue" name="Proformaconsolidatednetrevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_ProjectedDefinedBenefitPlanNetPeriodicBenefitCost" name="ProjectedDefinedBenefitPlanNetPeriodicBenefitCost" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_PropertyPlantAndEquipmentEstimatedUsefulLivesTableTextBlock" name="PropertyPlantAndEquipmentEstimatedUsefulLivesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" name="PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ProposedDamagesPerViolation" name="ProposedDamagesPerViolation" nillable="true" substitutionGroup="xbrli:item" type="us-types:perUnitItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_ReductionforPlaintiffNegligence" name="ReductionforPlaintiffNegligence" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ReimbursableOutofPocketExpensesPolicyPolicyTextBlock" name="ReimbursableOutofPocketExpensesPolicyPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_RestrictedStockAndPerformanceSharesAbstract" name="RestrictedStockAndPerformanceSharesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_RestrictedStockAndPerformanceSharesMember" name="RestrictedStockAndPerformanceSharesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_RestrictedStockAwardsAndPerformanceSharesSurrendered" name="RestrictedStockAwardsAndPerformanceSharesSurrendered" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_RestrictedStockPerformanceSharesExpense" name="RestrictedStockPerformanceSharesExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_RestructuringReserveSettledWithCashAndOtherAdjustment" name="RestructuringReserveSettledWithCashAndOtherAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_RoutineTestingMember" name="RoutineTestingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ScheduleOfOtherIntangibleAssetsByMajorClassAxis" name="ScheduleOfOtherIntangibleAssetsByMajorClassAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ScheduleOfOtherIntangibleAssetsByMajorClassDomain" name="ScheduleOfOtherIntangibleAssetsByMajorClassDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ScheduleToFinancialStatmentsAbstract" name="ScheduleToFinancialStatmentsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SeniorLongTermNotesDue2015Member" name="SeniorLongTermNotesDue2015Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SeniorLongTermNotesDue2020Member" name="SeniorLongTermNotesDue2020Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_SeniorNotesCurrent2014" name="SeniorNotesCurrent2014" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_SeniorNotesDue2016Member" name="SeniorNotesDue2016Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SeniorNotesDue2017Member" name="SeniorNotesDue2017Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SeniorNotesDue2020Member" name="SeniorNotesDue2020Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SeniorNotesDue2022Member" name="SeniorNotesDue2022Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_SeniorNotesFairValue" name="SeniorNotesFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_SeniorNotescurrent2015" name="SeniorNotescurrent2015" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2018Member" name="Seniornotesdue2018Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2023Member" name="Seniornotesdue2023Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2025Member" name="Seniornotesdue2025Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2025MemberMember" name="Seniornotesdue2025MemberMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2045Member" name="Seniornotesdue2045Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ShareBasedCompensationArrangementPerformanceShareAwardsVestingConditions" name="ShareBasedCompensationArrangementPerformanceShareAwardsVestingConditions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ShareBasedCompensationOptionAndIncentivePlansPolicyTextBlock" name="ShareBasedCompensationOptionAndIncentivePlansPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange01Member" name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange01Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange02Member" name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange02Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange03Member" name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange03Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange04Member" name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange04Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange05Member" name="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRange05Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_SharesAbstract" name="SharesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_SoftwareDepreciation" name="SoftwareDepreciation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_SpecialchargeSTequityretentionarrangement" name="SpecialchargeSTequityretentionarrangement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_Specialchargeacceleratedequitycompensation" name="Specialchargeacceleratedequitycompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_Specialchargewinddownofminvolumecontract" name="Specialchargewinddownofminvolumecontract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_StockConversionRateForZeroCouponSubordinatedNotes" name="StockConversionRateForZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_TaxBenefitRealizedUponConversionOfZeroCouponConvertibleDebt" name="TaxBenefitRealizedUponConversionOfZeroCouponConvertibleDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_TermLoanMember" name="TermLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Totalacquisitionconsiderationcashandnoncash" name="Totalacquisitionconsiderationcashandnoncash" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_Transactioncosts" name="Transactioncosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_TriStateClinicalLaboratoryServicesLlcMember" name="TriStateClinicalLaboratoryServicesLlcMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpenseBenefit" name="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpenseBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" name="UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_UsFixedIncomeMember" name="UsFixedIncomeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_UsLargeCapBlendMember" name="UsLargeCapBlendMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_UsMidCapBlendMember" name="UsMidCapBlendMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_UsSmallCapBlendMember" name="UsSmallCapBlendMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ValuationAndQualifyingAccountsDisclosureTextBlock" name="ValuationAndQualifyingAccountsDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod" name="ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_Writeoffofbridgeandotherdeferredfinancingcosts" name="Writeoffofbridgeandotherdeferredfinancingcosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_ZeroCouponConvertibleSubordinatedNotesConversionTriggerPrice" name="ZeroCouponConvertibleSubordinatedNotesConversionTriggerPrice" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_ZeroCouponNotesFairValue" name="ZeroCouponNotesFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
</xsd:schema>
</XBRL>
