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		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="IncreaseDecreaseInAccountsPayable" xlink:title="IncreaseDecreaseInAccountsPayable"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="IncreaseDecreaseInAccountsPayable" xlink:title="calculation: NetCashProvidedByUsedInOperatingActivities to IncreaseDecreaseInAccountsPayable" use="optional" order="11.0" weight="1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="DeferredPaymentsOnAcquisitions" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to DeferredPaymentsOnAcquisitions" use="optional" order="3.0" weight="1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="PaymentsToAcquireShortTermInvestments" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to PaymentsToAcquireShortTermInvestments" use="optional" order="4.0" weight="-1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="ProceedsFromSaleOfShortTermInvestments" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to ProceedsFromSaleOfShortTermInvestments" use="optional" order="5.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="PaymentsToAcquireIntangibleAssets" xlink:title="PaymentsToAcquireIntangibleAssets"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="PaymentsToAcquireIntangibleAssets" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to PaymentsToAcquireIntangibleAssets" use="optional" order="6.0" weight="-1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:label="PaymentsToAcquireEquityMethodInvestments" xlink:title="PaymentsToAcquireEquityMethodInvestments"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="PaymentsToAcquireEquityMethodInvestments" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to PaymentsToAcquireEquityMethodInvestments" use="optional" order="7.0" weight="-1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:title="PaymentsToAcquireBusinessesNetOfCashAcquired"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInInvestingActivities" xlink:to="PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:title="calculation: NetCashProvidedByUsedInInvestingActivities to PaymentsToAcquireBusinessesNetOfCashAcquired" use="optional" order="8.0" weight="-1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="NetCashProvidedByUsedInFinancingActivities" xlink:title="calculation: CashAndCashEquivalentsPeriodIncreaseDecrease to NetCashProvidedByUsedInFinancingActivities" use="optional" order="3.0" weight="1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="ProceedsFromLongTermLinesOfCredit" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to ProceedsFromLongTermLinesOfCredit" use="optional" order="2.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="RepaymentsOfLongTermLinesOfCredit" xlink:title="RepaymentsOfLongTermLinesOfCredit"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="RepaymentsOfLongTermLinesOfCredit" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to RepaymentsOfLongTermLinesOfCredit" use="optional" order="3.0" weight="-1.0"/>
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		<link:loc xlink:type="locator" xlink:href="lh-20091231.xsd#lh_PaymentsOnZeroCouponSubordinatedNotes" xlink:label="PaymentsOnZeroCouponSubordinatedNotes" xlink:title="PaymentsOnZeroCouponSubordinatedNotes"/>
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		<link:loc xlink:type="locator" xlink:href="lh-20091231.xsd#lh_PaymentsOnVendorFinancedEquipment" xlink:label="PaymentsOnVendorFinancedEquipment" xlink:title="PaymentsonVendorFinancedEquipment"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="ProceedsFromRepaymentsOfBankOverdrafts" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to ProceedsFromRepaymentsOfBankOverdrafts" use="optional" order="7.0" weight="1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="PaymentsOfDebtIssuanceCosts" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to PaymentsOfDebtIssuanceCosts" use="optional" order="9.0" weight="-1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsOfDividendsMinorityInterest" xlink:label="PaymentsOfDividendsMinorityInterest" xlink:title="PaymentsOfDividendsMinorityInterest"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="PaymentsOfDividendsMinorityInterest" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to PaymentsOfDividendsMinorityInterest" use="optional" order="10.0" weight="-1.0"/>
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		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="NetProceedsFromIssuanceOfStockToEmployees" xlink:title="calculation: NetCashProvidedByUsedInFinancingActivities to NetProceedsFromIssuanceOfStockToEmployees" use="optional" order="12.0" weight="1.0"/>
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		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="EffectOfExchangeRateOnCashAndCashEquivalents" xlink:title="EffectOfExchangeRateOnCashAndCashEquivalents"/>
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  <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_loc_ProceedsFromIssuanceOfLongTermDebt" xlink:type="arc"/></link:calculationLink>
	<link:calculationLink xlink:type="extended" xlink:role="http://labcorp.com/role/ConsolidatedStatementsOfOperations">
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss"/>
		<link:loc xlink:type="locator" xlink:href="lh-20091231.xsd#lh_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterest"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="ProfitLoss" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" xlink:title="calculation: ProfitLoss to IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" use="optional" order="1.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest" xlink:to="OperatingIncomeLoss" xlink:title="calculation: IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndMinorityInterest to OperatingIncomeLoss" use="optional" order="1.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_GrossProfit" xlink:label="GrossProfit" xlink:title="GrossProfit"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="OperatingIncomeLoss" xlink:to="GrossProfit" xlink:title="calculation: OperatingIncomeLoss to GrossProfit" use="optional" order="1.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="SalesRevenueNet" xlink:title="SalesRevenueNet"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="GrossProfit" xlink:to="SalesRevenueNet" xlink:title="calculation: GrossProfit to SalesRevenueNet" use="optional" order="1.0" weight="1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="CostOfGoodsAndServicesSold" xlink:title="CostOfGoodsAndServicesSold"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="GrossProfit" xlink:to="CostOfGoodsAndServicesSold" xlink:title="calculation: GrossProfit to CostOfGoodsAndServicesSold" use="optional" order="2.0" weight="-1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="SellingGeneralAndAdministrativeExpense" xlink:title="SellingGeneralAndAdministrativeExpense"/>
		<link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="OperatingIncomeLoss" xlink:to="SellingGeneralAndAdministrativeExpense" xlink:title="calculation: OperatingIncomeLoss to SellingGeneralAndAdministrativeExpense" use="optional" order="2.0" weight="-1.0"/>
		<link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets"/>
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