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  <xs:element id="lh_NoteReceivableCreditLossExpenseReversal" abstract="false" name="NoteReceivableCreditLossExpenseReversal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_CommonSharesIssuedRollforwardAbstract" abstract="true" name="CommonSharesIssuedRollforwardAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_IncrementalCommonSharesAttributableToStockOptions" abstract="false" name="IncrementalCommonSharesAttributableToStockOptions" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="lh_InterestPaidInCash" abstract="false" name="InterestPaidInCash" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_LongTermContractsDurationMaximum" abstract="false" name="LongTermContractsDurationMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="lh_LongTermDebtExcludingDebtIssuanceCosts" abstract="false" name="LongTermDebtExcludingDebtIssuanceCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_IncomeAbstract" abstract="true" name="IncomeAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_Maximumdeferralpercentageofannualcashincentivepay" abstract="false" name="Maximumdeferralpercentageofannualcashincentivepay" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="lh_Longtermdebtfutureminimumpaymentsinterestincludedinpayments" abstract="false" name="Longtermdebtfutureminimumpaymentsinterestincludedinpayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" 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_ShortTermLeaseMember" abstract="true" name="ShortTermLeaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan" abstract="false" name="AccountsreceivablefromOntariogovernmentsponsoredhealthcareplan" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_CashPaidDuringPeriodForAbstract" abstract="true" name="CashPaidDuringPeriodForAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="lh_AscensionAcquisitionMember" abstract="true" name="AscensionAcquisitionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_A4.625SeniorNotesDue2020RedeemedValue" abstract="false" name="A4.625SeniorNotesDue2020RedeemedValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <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_EmployeeStockPurchasePlanPercentOfMarketPrice" abstract="false" name="EmployeeStockPurchasePlanPercentOfMarketPrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <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_A2.95seniornotesdue2029" abstract="false" name="A2.95seniornotesdue2029" 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_AccruedTaxInterestAddedfromAcquisition" abstract="false" name="AccruedTaxInterestAddedfromAcquisition" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_A2019TermLoan" abstract="false" name="A2019TermLoan" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_FacilityRelatedRestructuringReserveAccrualAdjustment" abstract="false" name="FacilityRelatedRestructuringReserveAccrualAdjustment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_A270SeniorNotesDue2031" abstract="false" name="A270SeniorNotesDue2031" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <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_Seniornotesdue2027" abstract="false" name="Seniornotesdue2027" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_AllowanceforCreditLoss" abstract="false" name="AllowanceforCreditLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_SalesCommissionAmortizationPeriodMinimum" abstract="false" name="SalesCommissionAmortizationPeriodMinimum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="lh_A2020AcquisitionsMember" abstract="true" name="A2020AcquisitionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" abstract="false" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ChangesInCommonSharesIssuedAndHeldInTreasuryTableTextBlock" abstract="false" name="ChangesInCommonSharesIssuedAndHeldInTreasuryTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_InternalUseSoftwarePolicyTextBlock" abstract="false" name="InternalUseSoftwarePolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_CostMethodInvestmentsMaximumOwnershipPercentage" abstract="false" name="CostMethodInvestmentsMaximumOwnershipPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="lh_SeniorNotesDueAugust2022Member" abstract="true" name="SeniorNotesDueAugust2022Member" 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:element id="lh_Percentofgrossaccountsreceivableduefrompatients" abstract="false" name="Percentofgrossaccountsreceivableduefrompatients" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="lh_AssumedBenefitPaymentsByYearTableTextBlock" abstract="false" name="AssumedBenefitPaymentsByYearTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="lh_PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" abstract="false" name="PropertyPlantAndEquipmentUsefulLifeSoftwareAverage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
  <xs:element id="lh_EmployeeStockPurchasePlanMember" abstract="true" name="EmployeeStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <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_TotalShortandLongTermDebtIssuanceCosts" abstract="false" name="TotalShortandLongTermDebtIssuanceCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="lh_ThirdpartyMember" abstract="true" name="ThirdpartyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="lh_InProcessAssetsMember" abstract="true" name="InProcessAssetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
