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  <xs:element id="lh_NoteReceivableAllowanceforCreditLoss" abstract="false" name="NoteReceivableAllowanceforCreditLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="lh_Seniornotesdue2027" abstract="false" name="Seniornotesdue2027" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="lh_IssuanceOfCommonStockUnderEmployeeStockPlans" abstract="false" name="IssuanceOfCommonStockUnderEmployeeStockPlans" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" abstract="false" name="PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
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  <xs:element id="lh_CommonSharesHeldInTreasuryRollforwardAbstract" abstract="true" name="CommonSharesHeldInTreasuryRollforwardAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_PatentsLicensesAndTechnologyMember" abstract="true" name="PatentsLicensesAndTechnologyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_AssumedBenefitPaymentsByYearTableTextBlock" abstract="false" name="AssumedBenefitPaymentsByYearTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
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  <xs:element id="lh_CashPaidDuringPeriodForAbstract" abstract="true" name="CashPaidDuringPeriodForAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" abstract="false" name="UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ShareBasedCompensationOptionAndIncentivePlansPolicyTextBlock" abstract="false" name="ShareBasedCompensationOptionAndIncentivePlansPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_A2.30seniornotesdue2024" abstract="false" name="A2.30seniornotesdue2024" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ProfessionalLiabilityPolicyTextBlock" abstract="false" name="ProfessionalLiabilityPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_UnbilledServicesAllowanceforCreditLoss" abstract="false" name="UnbilledServicesAllowanceforCreditLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_UsFixedIncomeMember" abstract="true" name="UsFixedIncomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_CommonSharesIssuedRollforwardAbstract" abstract="true" name="CommonSharesIssuedRollforwardAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_Shorttermdebtissuancecosts" abstract="false" name="Shorttermdebtissuancecosts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_TotalShortandLongTermDebtIssuanceCosts" abstract="false" name="TotalShortandLongTermDebtIssuanceCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ForeignTaxLossCarryovers" abstract="false" name="ForeignTaxLossCarryovers" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_UnbilledServicesCreditLossExpenseReversal" abstract="false" name="UnbilledServicesCreditLossExpenseReversal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_UKPlanMember" abstract="true" name="UKPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_ReversalofAccruedIncomeTaxPenaltiesAndInterest" abstract="false" name="ReversalofAccruedIncomeTaxPenaltiesAndInterest" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_Maximumdeferralpercentageofannualbasesalary" abstract="false" name="Maximumdeferralpercentageofannualbasesalary" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="lh_AllowanceforCreditLossWriteOff" abstract="false" name="AllowanceforCreditLossWriteOff" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ForeignTaxLossCarryoversExpirein2034" abstract="false" name="ForeignTaxLossCarryoversExpirein2034" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_MedicareandMedicaidMember" abstract="true" name="MedicareandMedicaidMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_ShortTermDebtAndLongTermDebtCurrentMaturities" abstract="false" name="ShortTermDebtAndLongTermDebtCurrentMaturities" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_EmployeeStockPurchasePlanNumberOfSharesPurchased" abstract="false" name="EmployeeStockPurchasePlanNumberOfSharesPurchased" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="lh_A2019AcquisitionsMember" abstract="true" name="A2019AcquisitionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_Post2017Member" abstract="true" name="Post2017Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_ExcludingEnvigoMember" abstract="true" name="ExcludingEnvigoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_PropertyPlantAndEquipmentEstimatedUsefulLivesTableTextBlock" abstract="false" name="PropertyPlantAndEquipmentEstimatedUsefulLivesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_CreditLossExpenseReversal" abstract="false" name="CreditLossExpenseReversal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_FederalandStateAttributeCarryforwards" abstract="false" name="FederalandStateAttributeCarryforwards" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_PercentOfDomesticRevenue" abstract="false" name="PercentOfDomesticRevenue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="lh_IncreaseDecreaseInNoncontrollingInterestPut" abstract="false" name="IncreaseDecreaseInNoncontrollingInterestPut" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_FairValueLiabilitiesMeasuredOnRecurringBasisDeferredCompensationLiability" abstract="false" name="FairValueLiabilitiesMeasuredOnRecurringBasisDeferredCompensationLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_FairValueLiabilitiesMeasuredOnRecurringBasisNoncontrollingInterestPuts" abstract="false" name="FairValueLiabilitiesMeasuredOnRecurringBasisNoncontrollingInterestPuts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_BalanceOfSeniorNotesMatureDuringQ42020" abstract="false" name="BalanceOfSeniorNotesMatureDuringQ42020" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ShortTermDebtIssueCostsMember" abstract="true" name="ShortTermDebtIssueCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_DefinedBenefitPlanExpectedRateOfReturnOnAssetsOtherAssets" abstract="false" name="DefinedBenefitPlanExpectedRateOfReturnOnAssetsOtherAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
</xs:schema>
