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  <xsd:element abstract="true" id="lh_FairValuesOptionsAndPurchaseRightAbstract" name="FairValuesOptionsAndPurchaseRightAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_FederalTaxLossCarryforwardsIndefinite" name="FederalTaxLossCarryforwardsIndefinite" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <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_FederalandStateAttributeCarryforwardValuationAllowance" name="FederalandStateAttributeCarryforwardValuationAllowance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_FederalandStateAttributeCarryforwards" name="FederalandStateAttributeCarryforwards" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_FlorenceSouthCarolinaMember" name="FlorenceSouthCarolinaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ForeignTaxLossCarryoverValuationAllowance" name="ForeignTaxLossCarryoverValuationAllowance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" 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_ForeignTaxLossCarryoversExpirein2034" name="ForeignTaxLossCarryoversExpirein2034" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_GainRecognizedonExitofInterestRateSwapArrangement" name="GainRecognizedonExitofInterestRateSwapArrangement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_GreaterThanLeaseTermMonthsRequiredtoRecordRightofUseAssetandLeaseLiability" name="GreaterThanLeaseTermMonthsRequiredtoRecordRightofUseAssetandLeaseLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" 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 id="lh_IncrementalCommonSharesAttributableToStockOptions" name="IncrementalCommonSharesAttributableToStockOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_IntangibleAssetsFiniteLivedPolicyTextBlock" name="IntangibleAssetsFiniteLivedPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Intercompanyrevenueelimination" name="Intercompanyrevenueelimination" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <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 abstract="true" id="lh_LabCorpDiagnosticsMember" name="LabCorpDiagnosticsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Leasesnotyetcommenced" name="Leasesnotyetcommenced" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_LessThanInitialLeaseTermMonthsForShortTermLeaseExemptionandRecordingonBalanceSheet" name="LessThanInitialLeaseTermMonthsForShortTermLeaseExemptionandRecordingonBalanceSheet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_LongLivedAssetsPolicyTextBlock" name="LongLivedAssetsPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_LongTermContractsDurationMaximum" name="LongTermContractsDurationMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_LongTermContractsDurationMinimum" name="LongTermContractsDurationMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <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_Longtermdebtissuancecosts" name="Longtermdebtissuancecosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <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 abstract="true" id="lh_MedicareandMedicaidMember" name="MedicareandMedicaidMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" 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_NetProceedsFromIssuanceOfStockToEmployees" name="NetProceedsFromIssuanceOfStockToEmployees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NetRestructuringAndOtherSpecialCharges" name="NetRestructuringAndOtherSpecialCharges" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NetRestructuringCharges" name="NetRestructuringCharges" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NettaximpactofGILTI" name="NettaximpactofGILTI" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NettaximpactofTCJA" name="NettaximpactofTCJA" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_NonElectiveContribution" name="NonElectiveContribution" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Noncashconversionofzerocouponconvertibledebt" name="Noncashconversionofzerocouponconvertibledebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_NoncontrollingInterestMezzanineEquity" name="NoncontrollingInterestMezzanineEquity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="lh_NumberOfDaysUsedToEstablishAverageMarketPriceOfZeroCouponSubordinatedNotes" name="NumberOfDaysUsedToEstablishAverageMarketPriceOfZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:normalizedStringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_NumberofAdditionalPartiesNotProvidingConsent" name="NumberofAdditionalPartiesNotProvidingConsent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" 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_OtherFinancingCashFlows" name="OtherFinancingCashFlows" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_OtherLiabilitiesNoncurrentOther" name="OtherLiabilitiesNoncurrentOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_OtheracquireesMember" name="OtheracquireesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" 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 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_PaymentsOnZeroCouponSubordinatedNotes" name="PaymentsOnZeroCouponSubordinatedNotes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_PensionEqualizationPlanMember" name="PensionEqualizationPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" 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_PercentageChangeinDiscountRateUsedtoCalculateFairValueofGoodwill" name="PercentageChangeinDiscountRateUsedtoCalculateFairValueofGoodwill" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_PercentageFairValueExceedsCarryingValuewitha1ChangeinDiscountRateUsedtoCalculateFairValueofGoodwill" name="PercentageFairValueExceedsCarryingValuewitha1ChangeinDiscountRateUsedtoCalculateFairValueofGoodwill" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="lh_PercentageFairValueofGoodwillExceededCarryingValue" name="PercentageFairValueofGoodwillExceededCarryingValue" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <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_Percentofremainingperformanceobligationsrecognizedasrevenueinnextyear" name="Percentofremainingperformanceobligationsrecognizedasrevenueinnextyear" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <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_ProfessionalLiabilityPolicyTextBlock" name="ProfessionalLiabilityPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" 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_Propertyplantandequipmentusefullifesoftwaremaximum" name="Propertyplantandequipmentusefullifesoftwaremaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Propertyplantandequipmentusefullifesoftwareminimum" name="Propertyplantandequipmentusefullifesoftwareminimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" 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_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 id="lh_ReversalofAccruedIncomeTaxPenaltiesAndInterest" name="ReversalofAccruedIncomeTaxPenaltiesAndInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="lh_SalesCommissionAmortizationPeriodMaximum" name="SalesCommissionAmortizationPeriodMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_SalesCommissionAmortizationPeriodMinimum" name="SalesCommissionAmortizationPeriodMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" 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 id="lh_ScheduleofAmountsRecognizedinAccumulatedOtherComprehensiveIncomeforUKPlansandGermanyPlanTableTextBlock" name="ScheduleofAmountsRecognizedinAccumulatedOtherComprehensiveIncomeforUKPlansandGermanyPlanTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ScheduleofUKPlansTargetAssetAllocationsTableTextBlock" name="ScheduleofUKPlansTargetAssetAllocationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_ScheduleofWeightedAverageAssetAllocationforUKPensionPlansbyAssetCategoryTableTextBlock" name="ScheduleofWeightedAverageAssetAllocationforUKPensionPlansbyAssetCategoryTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" 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 abstract="true" id="lh_SeniorNotesDue2020Member" name="SeniorNotesDue2020Member" 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_Seniornotesdue2024" name="Seniornotesdue2024" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2024MemberMember" name="Seniornotesdue2024MemberMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Seniornotesdue2027" name="Seniornotesdue2027" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2027Member" name="Seniornotesdue2027Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_Seniornotesdue2029Member" name="Seniornotesdue2029Member" 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_SharesAbstract" name="SharesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_Shorttermdebtissuancecosts" name="Shorttermdebtissuancecosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <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_Taxbenefitrealizeduponconversionofzerocouponconvertibledebt" name="Taxbenefitrealizeduponconversionofzerocouponconvertibledebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_ThirdpartyMember" name="ThirdpartyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_TotalShortandLongTermDebtIssuanceCosts" name="TotalShortandLongTermDebtIssuanceCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_Totalacquisitionconsiderationcashstocknotesetc." name="Totalacquisitionconsiderationcashstocknotesetc." nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="lh_UKforensictestingservicesbusinessMember" name="UKforensictestingservicesbusinessMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="lh_USforensictestingservicesbusinessMember" name="USforensictestingservicesbusinessMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="lh_UnrecognizedTaxBenefitsIncreaseinReserveFromAcquisition" name="UnrecognizedTaxBenefitsIncreaseinReserveFromAcquisition" 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_ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod" name="ValueOfCashAndCommonStockInConnectionWithConversionsOfZeroCouponSubordinatedNotesSettledInCurrentPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="lh_ValueofCommonStockRepurchased" name="ValueofCommonStockRepurchased" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_ValueofCommonStockRepurchasedPriortoNewPlan" name="ValueofCommonStockRepurchasedPriortoNewPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="lh_ValueofReportingUnitsGoodwill" name="ValueofReportingUnitsGoodwill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" 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>
