<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:f8591a9d-3a14-49c1-aec1-255af55e4a01,g:88e9c9a6-7741-4704-8018-e90ab91643d2-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.orasure.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="osur-20250930.xsd#ConsolidatedBalanceSheets"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_40c6aac7-5210-4480-a6a5-9c98ec7a612f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_34c92e40-9397-4274-ab4f-ad9e5b42a77b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_40c6aac7-5210-4480-a6a5-9c98ec7a612f" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_34c92e40-9397-4274-ab4f-ad9e5b42a77b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_69d46377-9c2e-4494-8c65-a1d568959f13" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_40c6aac7-5210-4480-a6a5-9c98ec7a612f" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_69d46377-9c2e-4494-8c65-a1d568959f13" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_f96784ea-4c19-4833-a198-fcc94a3ed228" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_40c6aac7-5210-4480-a6a5-9c98ec7a612f" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_f96784ea-4c19-4833-a198-fcc94a3ed228" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_6b422eac-93b3-4aa6-b0b1-b586c35dbf0d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_40c6aac7-5210-4480-a6a5-9c98ec7a612f" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_6b422eac-93b3-4aa6-b0b1-b586c35dbf0d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_6d1981d9-704f-4c2a-ae27-2e328776c819" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_f963dfe3-f06d-48f9-9304-a3ccc331b2f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_6d1981d9-704f-4c2a-ae27-2e328776c819" xlink:to="loc_us-gaap_AssetsCurrent_f963dfe3-f06d-48f9-9304-a3ccc331b2f0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrent_4f405cf7-9d4e-449f-9be7-438e5afcfb98" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_6d1981d9-704f-4c2a-ae27-2e328776c819" xlink:to="loc_us-gaap_AssetsNoncurrent_4f405cf7-9d4e-449f-9be7-438e5afcfb98" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_a3081f03-af5e-4231-9b34-e9939eff5a21" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_e3fdb04a-9a5a-4305-80fb-533fc3d7ad6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_a3081f03-af5e-4231-9b34-e9939eff5a21" xlink:to="loc_us-gaap_LiabilitiesCurrent_e3fdb04a-9a5a-4305-80fb-533fc3d7ad6b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_daf333e3-0b88-4be7-86b0-fd70d0dfb0a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_a3081f03-af5e-4231-9b34-e9939eff5a21" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_daf333e3-0b88-4be7-86b0-fd70d0dfb0a7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_a0fbfff4-ec4b-4c59-8c00-47209a706024" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_a0fbfff4-ec4b-4c59-8c00-47209a706024" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFVNINoncurrent_f89d3828-8d6f-44fe-b9ea-163321c39b83" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFVNINoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_EquitySecuritiesFVNINoncurrent_f89d3828-8d6f-44fe-b9ea-163321c39b83" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_8e26f090-6a9b-4b9f-9ec5-480c36ec2223" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_8e26f090-6a9b-4b9f-9ec5-480c36ec2223" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_a186533a-e052-4d71-9668-4bf067712768" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_Goodwill_a186533a-e052-4d71-9668-4bf067712768" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_0d781da3-bffd-4968-8718-bdd65f80be4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_0d781da3-bffd-4968-8718-bdd65f80be4c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset_daa49ad3-e9cf-4890-acd5-620202bfa6af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAsset_daa49ad3-e9cf-4890-acd5-620202bfa6af" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_b7e1c366-31c5-4d87-84d2-f20cf747c531" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_b7e1c366-31c5-4d87-84d2-f20cf747c531" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_7e45f08f-7968-48ec-b754-e736e731870c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsNoncurrent_7a6f2e1c-bd8d-4386-a195-93fbeb30972d" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_7e45f08f-7968-48ec-b754-e736e731870c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_da322fb8-1097-4636-a97d-209d23e4654b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_us-gaap_AccountsPayableCurrent_da322fb8-1097-4636-a97d-209d23e4654b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_4547497d-540e-4157-b793-8acf0c804ba6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_4547497d-540e-4157-b793-8acf0c804ba6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_0408b82c-31f7-422d-a326-2cbf63f69eab" xlink:href="osur-20250930.xsd#osur_AccruedExpensesAndOtherCurrentLiabilities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_0408b82c-31f7-422d-a326-2cbf63f69eab" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_b106948c-dd7c-4686-a7d2-b15dbef843ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_b106948c-dd7c-4686-a7d2-b15dbef843ce" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_f7a9fe21-18e2-460d-928d-212008f783ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_f7a9fe21-18e2-460d-928d-212008f783ed" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_1c13a01c-66c5-458a-bf57-5d9f96e8b2e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_8f5b4777-4c42-4a5e-ac14-505a77ab2573" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_1c13a01c-66c5-458a-bf57-5d9f96e8b2e7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_7ac0f628-c28e-4290-9430-75af44300f61" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_1a337a72-0136-47ec-bd09-865740a82b25" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_7ac0f628-c28e-4290-9430-75af44300f61" xlink:to="loc_us-gaap_Liabilities_1a337a72-0136-47ec-bd09-865740a82b25" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_e128be73-3e29-48ae-9966-855f4c5c8c7f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_7ac0f628-c28e-4290-9430-75af44300f61" xlink:to="loc_us-gaap_CommitmentsAndContingencies_e128be73-3e29-48ae-9966-855f4c5c8c7f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_a9178ed3-b50d-49eb-85a6-374b059d8e1a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_7ac0f628-c28e-4290-9430-75af44300f61" xlink:to="loc_us-gaap_StockholdersEquity_a9178ed3-b50d-49eb-85a6-374b059d8e1a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_d4d27ee1-0b9e-4dd5-8644-ff922a4d27c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:to="loc_us-gaap_PreferredStockValue_d4d27ee1-0b9e-4dd5-8644-ff922a4d27c5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_82cacf2c-32e6-48ff-82d2-a5f07fa6d612" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:to="loc_us-gaap_CommonStockValue_82cacf2c-32e6-48ff-82d2-a5f07fa6d612" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_cce96a0f-a823-4c51-bdcc-1ab7168d4c82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_cce96a0f-a823-4c51-bdcc-1ab7168d4c82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_90794a1e-9702-4db5-8b20-0679eafba19e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_90794a1e-9702-4db5-8b20-0679eafba19e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_3c839733-12cd-41a5-acc5-37bc333efa27" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_2bacebf5-bed7-49c7-8241-0b7e1d68bce8" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_3c839733-12cd-41a5-acc5-37bc333efa27" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1d516572-ac63-4947-a2cd-fecdd22bfcd4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1d516572-ac63-4947-a2cd-fecdd22bfcd4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_67c558d1-27e2-4423-baad-88ebfdfc04ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_67c558d1-27e2-4423-baad-88ebfdfc04ce" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_bbf55346-8578-4f86-b418-67f875621069" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:to="loc_us-gaap_InventoryNet_bbf55346-8578-4f86-b418-67f875621069" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_be25930b-4f01-4d87-989d-3a25bc0389ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_be25930b-4f01-4d87-989d-3a25bc0389ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_5a6753cf-c466-4d5d-a348-c48650e532fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_01b9b6bf-6d7b-4d30-9d62-201ba02cbf69" xlink:to="loc_us-gaap_OtherAssetsCurrent_5a6753cf-c466-4d5d-a348-c48650e532fb" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="osur-20250930.xsd#ConsolidatedStatementsofOperations"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/ConsolidatedStatementsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_303885bb-cfc0-436c-a0d9-1660c3ff8013" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_de15cb8f-3429-4283-92a6-5d4a36ad354f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_303885bb-cfc0-436c-a0d9-1660c3ff8013" xlink:to="loc_us-gaap_OperatingIncomeLoss_de15cb8f-3429-4283-92a6-5d4a36ad354f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncome_dedcee6a-da67-4571-8f8a-89775e43c403" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncome"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_303885bb-cfc0-436c-a0d9-1660c3ff8013" xlink:to="loc_us-gaap_OtherNonoperatingIncome_dedcee6a-da67-4571-8f8a-89775e43c403" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_618cf42e-39a4-4f32-af39-b840447b47cb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_2c70ace4-0ea2-4c03-ba31-2660f014d066" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_618cf42e-39a4-4f32-af39-b840447b47cb" xlink:to="loc_us-gaap_GrossProfit_2c70ace4-0ea2-4c03-ba31-2660f014d066" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_d6bc73ec-3467-4196-b20a-a4d05b1b2074" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_618cf42e-39a4-4f32-af39-b840447b47cb" xlink:to="loc_us-gaap_OperatingExpenses_d6bc73ec-3467-4196-b20a-a4d05b1b2074" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_c3ec76b7-5aec-4359-a472-c2ab00f55d86" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax_be9aad39-5d8f-491f-a5d6-29210d3b47bb" xlink:href="osur-20250930.xsd#osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_c3ec76b7-5aec-4359-a472-c2ab00f55d86" xlink:to="loc_osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax_be9aad39-5d8f-491f-a5d6-29210d3b47bb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_6eaa98f4-8e23-4fde-ac79-ae8213100b68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_c3ec76b7-5aec-4359-a472-c2ab00f55d86" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_6eaa98f4-8e23-4fde-ac79-ae8213100b68" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax_259dce4b-0a05-48d5-b348-266ba1dd0160" xlink:href="osur-20250930.xsd#osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_7d03994f-bcf6-4714-bd0b-9f4c5a1580a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax_259dce4b-0a05-48d5-b348-266ba1dd0160" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_7d03994f-bcf6-4714-bd0b-9f4c5a1580a6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_ebf3b351-2307-4302-8153-9c6946e251f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNetOfTax_259dce4b-0a05-48d5-b348-266ba1dd0160" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_ebf3b351-2307-4302-8153-9c6946e251f3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_3f5af3ff-01b4-400e-a99c-252c14675afc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_46b4bfd1-554b-48e2-bb0d-852dae116bca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_3f5af3ff-01b4-400e-a99c-252c14675afc" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_46b4bfd1-554b-48e2-bb0d-852dae116bca" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_81537c2b-f075-406e-a8c6-c806ea632d3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_3f5af3ff-01b4-400e-a99c-252c14675afc" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_81537c2b-f075-406e-a8c6-c806ea632d3f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_f4945614-4ea6-41a4-82ae-a32db17f0155" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_f4945614-4ea6-41a4-82ae-a32db17f0155" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_619f2a1f-517a-49ae-8368-9c6c3fff2eec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_SellingAndMarketingExpense_619f2a1f-517a-49ae-8368-9c6c3fff2eec" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_2c23271b-df71-4d06-aa70-71e57dbd4ee3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_2c23271b-df71-4d06-aa70-71e57dbd4ee3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_dd4d0e8f-e3d3-4ad8-b37c-c166394529e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_AssetImpairmentCharges_dd4d0e8f-e3d3-4ad8-b37c-c166394529e8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_3961ce15-d950-48d0-9135-0cdda5f57c2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_3961ce15-d950-48d0-9135-0cdda5f57c2b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_137655d4-b3e8-4760-adb8-6523580b0dec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_c05716a1-f359-4069-a6cc-31370e321249" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_137655d4-b3e8-4760-adb8-6523580b0dec" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/ConsolidatedStatementsofComprehensiveIncomeLoss" xlink:type="simple" xlink:href="osur-20250930.xsd#ConsolidatedStatementsofComprehensiveIncomeLoss"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/ConsolidatedStatementsofComprehensiveIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_2c40a769-18d5-462b-9900-eda0d20fe75d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_e26f5e1f-20ac-432b-b6ae-09fa6be34d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_2c40a769-18d5-462b-9900-eda0d20fe75d" xlink:to="loc_us-gaap_NetIncomeLoss_e26f5e1f-20ac-432b-b6ae-09fa6be34d7b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_d88b5cd0-5e3d-41aa-984b-26dc43143837" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_2c40a769-18d5-462b-9900-eda0d20fe75d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_d88b5cd0-5e3d-41aa-984b-26dc43143837" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/ConsolidatedStatementsofCashFlows" xlink:type="simple" xlink:href="osur-20250930.xsd#ConsolidatedStatementsofCashFlows"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/ConsolidatedStatementsofCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_26562cbc-26ac-410f-93d7-74a53a1598b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_dfcb01a1-4302-4b7a-8cda-08ccba09b472" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_26562cbc-26ac-410f-93d7-74a53a1598b0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_dfcb01a1-4302-4b7a-8cda-08ccba09b472" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_d71248f8-bc6c-4d63-862f-dc622fe1581c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_26562cbc-26ac-410f-93d7-74a53a1598b0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_d71248f8-bc6c-4d63-862f-dc622fe1581c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_79df7384-074b-4c5a-a4cc-c8d150784bed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_26562cbc-26ac-410f-93d7-74a53a1598b0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_79df7384-074b-4c5a-a4cc-c8d150784bed" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_c36057f6-e696-4f54-8e08-5cbcdb7c2312" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_26562cbc-26ac-410f-93d7-74a53a1598b0" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_c36057f6-e696-4f54-8e08-5cbcdb7c2312" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_a17e96f6-766a-499b-99c5-9639e4c68af1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_a17e96f6-766a-499b-99c5-9639e4c68af1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_9f7463d3-f1e1-47f5-b53d-75e2b58c6cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_9f7463d3-f1e1-47f5-b53d-75e2b58c6cb8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_67d4e518-567c-445f-a0c0-84805eb0d5ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_67d4e518-567c-445f-a0c0-84805eb0d5ff" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_96d309c4-15cf-456a-bf1c-a5a385636fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:to="loc_us-gaap_ProceedsFromSaleOfProductiveAssets_96d309c4-15cf-456a-bf1c-a5a385636fa1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2edbe515-406d-4802-b6f4-53b5d7f7771d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_474898c2-95c8-46ca-aa92-ac25c56e2d78" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2edbe515-406d-4802-b6f4-53b5d7f7771d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6e676af4-0f90-4e2b-a99d-a2680428a667" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments_59fdf4ec-72ea-4b57-b917-19a20162e805" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6e676af4-0f90-4e2b-a99d-a2680428a667" xlink:to="loc_us-gaap_FinanceLeasePrincipalPayments_59fdf4ec-72ea-4b57-b917-19a20162e805" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_e65a508b-c2e1-45a6-b30c-c39b72d2fc16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6e676af4-0f90-4e2b-a99d-a2680428a667" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_e65a508b-c2e1-45a6-b30c-c39b72d2fc16" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_85bae89a-01f1-43c8-9d25-b284d9b9b521" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6e676af4-0f90-4e2b-a99d-a2680428a667" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_85bae89a-01f1-43c8-9d25-b284d9b9b521" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_0bc47927-8450-4a6a-80ed-f60beb64f2df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6e676af4-0f90-4e2b-a99d-a2680428a667" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_0bc47927-8450-4a6a-80ed-f60beb64f2df" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a6646e5e-403a-4b2d-945a-2e4e00fa7173" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_NetIncomeLoss_a6646e5e-403a-4b2d-945a-2e4e00fa7173" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_7ead2e50-889f-4274-8b76-66b8d6f92a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_ShareBasedCompensation_7ead2e50-889f-4274-8b76-66b8d6f92a0b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_45fa4b4d-3e30-4a0f-9293-82db49bafd72" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_45fa4b4d-3e30-4a0f-9293-82db49bafd72" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_55dd5a3a-f46b-4041-a9e1-95100fa6b1c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_AssetImpairmentCharges_55dd5a3a-f46b-4041-a9e1-95100fa6b1c9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_osur_IncreaseDecreaseInOtherNonCashAmortization_242b9140-cb2a-4048-a06a-cb97b28bcee0" xlink:href="osur-20250930.xsd#osur_IncreaseDecreaseInOtherNonCashAmortization"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_osur_IncreaseDecreaseInOtherNonCashAmortization_242b9140-cb2a-4048-a06a-cb97b28bcee0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_da1448af-27e6-49e0-b3eb-b42e3795f810" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_da1448af-27e6-49e0-b3eb-b42e3795f810" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossUnrealized_38943470-0930-4ea6-925e-1160676d2f90" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCurrencyTransactionGainLossUnrealized"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossUnrealized_38943470-0930-4ea6-925e-1160676d2f90" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense_51d6ffc9-3bd6-4200-9831-599bd6834ac5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_FinanceLeaseInterestExpense_51d6ffc9-3bd6-4200-9831-599bd6834ac5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_e5777693-e89d-4536-9f7d-4af58e5d1f93" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_e5777693-e89d-4536-9f7d-4af58e5d1f93" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_e3ee6511-66ac-4e69-bae1-f95564f4e36f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_e3ee6511-66ac-4e69-bae1-f95564f4e36f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets_82991e6f-cf9d-454e-b146-7e35ba4305fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfOtherAssets"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_GainLossOnSaleOfOtherAssets_82991e6f-cf9d-454e-b146-7e35ba4305fb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_3c0d400e-fd5f-4a33-9db0-3a1d87c0e9ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_3c0d400e-fd5f-4a33-9db0-3a1d87c0e9ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_c5f710ad-326f-40ce-9bd7-c5709899158d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="13" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_c5f710ad-326f-40ce-9bd7-c5709899158d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_e190871d-1aaf-402d-9f7d-3eff5483b378" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:calculationArc order="14" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_e190871d-1aaf-402d-9f7d-3eff5483b378" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_934fe061-5b82-4d0b-a4d1-68447cc48d11" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:calculationArc order="15" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_934fe061-5b82-4d0b-a4d1-68447cc48d11" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_24cd9f63-52dc-4bbc-a6e7-ea21929eba4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="16" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_24cd9f63-52dc-4bbc-a6e7-ea21929eba4c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_1108930e-7b27-40d2-9862-7404a075aa0d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:calculationArc order="17" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_1108930e-7b27-40d2-9862-7404a075aa0d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_1b391120-90fa-4f25-af2a-22052e42beca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:calculationArc order="18" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4cab1c5-5d5f-4d68-8c26-e7f24e6c0973" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_1b391120-90fa-4f25-af2a-22052e42beca" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/SummaryofSignificantAccountingPoliciesScheduleofFairValueDetails" xlink:type="simple" xlink:href="osur-20250930.xsd#SummaryofSignificantAccountingPoliciesScheduleofFairValueDetails"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/SummaryofSignificantAccountingPoliciesScheduleofFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_bf9d3ce7-9d1a-4f78-8e4f-248302eefa15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_8978d88b-8589-4198-a4a0-1313218828b3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_bf9d3ce7-9d1a-4f78-8e4f-248302eefa15" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_8978d88b-8589-4198-a4a0-1313218828b3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_96f2cc89-4d38-4115-96e8-e013561fc1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_bf9d3ce7-9d1a-4f78-8e4f-248302eefa15" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_96f2cc89-4d38-4115-96e8-e013561fc1d2" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/InventoriesScheduleofInventoriesDetail" xlink:type="simple" xlink:href="osur-20250930.xsd#InventoriesScheduleofInventoriesDetail"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/InventoriesScheduleofInventoriesDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_4411dccc-67cb-49d7-be7a-8a4d6dab7474" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterialsNetOfReserves_6075ff41-082a-4511-9948-7af5d93fa129" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryRawMaterialsNetOfReserves"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_4411dccc-67cb-49d7-be7a-8a4d6dab7474" xlink:to="loc_us-gaap_InventoryRawMaterialsNetOfReserves_6075ff41-082a-4511-9948-7af5d93fa129" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWorkInProcess_75006c83-dc39-41df-9867-411ca3696f39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryWorkInProcess"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_4411dccc-67cb-49d7-be7a-8a4d6dab7474" xlink:to="loc_us-gaap_InventoryWorkInProcess_75006c83-dc39-41df-9867-411ca3696f39" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_d89162be-3a18-4178-922b-1f06a4e90900" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_4411dccc-67cb-49d7-be7a-8a4d6dab7474" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_d89162be-3a18-4178-922b-1f06a4e90900" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetail" xlink:type="simple" xlink:href="osur-20250930.xsd#PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetail"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_e4034f1b-e0fa-471f-9a58-6a66416c5067" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_d5b2fa29-6e15-44fe-9115-bd6896f1ea41" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_e4034f1b-e0fa-471f-9a58-6a66416c5067" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_d5b2fa29-6e15-44fe-9115-bd6896f1ea41" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_5697783c-fb1e-4e8d-8594-9d9bd7a4b5b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_e4034f1b-e0fa-471f-9a58-6a66416c5067" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_5697783c-fb1e-4e8d-8594-9d9bd7a4b5b5" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/AccruedExpensesandOtherCurrentLiabilitiesScheduleofAccruedExpensesandOtherCurrentLiabilitiesDetail" xlink:type="simple" xlink:href="osur-20250930.xsd#AccruedExpensesandOtherCurrentLiabilitiesScheduleofAccruedExpensesandOtherCurrentLiabilitiesDetail"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/AccruedExpensesandOtherCurrentLiabilitiesScheduleofAccruedExpensesandOtherCurrentLiabilitiesDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_262e317e-5d5e-4693-86d3-5412f4976075" xlink:href="osur-20250930.xsd#osur_AccruedExpensesAndOtherCurrentLiabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedProfessionalFeesCurrent_e906a7a5-4f0b-4d8b-a694-6bbe7c81b8cb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedProfessionalFeesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_262e317e-5d5e-4693-86d3-5412f4976075" xlink:to="loc_us-gaap_AccruedProfessionalFeesCurrent_e906a7a5-4f0b-4d8b-a694-6bbe7c81b8cb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_1f04b0d4-9b5e-46a1-8f8f-ea542a8ab3f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_262e317e-5d5e-4693-86d3-5412f4976075" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_1f04b0d4-9b5e-46a1-8f8f-ea542a8ab3f1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_fdab43d2-e00d-4a89-9f35-259b5fdd5c26" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_262e317e-5d5e-4693-86d3-5412f4976075" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_fdab43d2-e00d-4a89-9f35-259b5fdd5c26" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesAndExciseTaxPayableCurrent_b753859c-0312-4eeb-b21a-f50a566fd413" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SalesAndExciseTaxPayableCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_osur_AccruedExpensesAndOtherCurrentLiabilities_262e317e-5d5e-4693-86d3-5412f4976075" xlink:to="loc_us-gaap_SalesAndExciseTaxPayableCurrent_b753859c-0312-4eeb-b21a-f50a566fd413" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/IncomeTaxesSummaryOfIncomeTaxExpenseDetails" xlink:type="simple" xlink:href="osur-20250930.xsd#IncomeTaxesSummaryOfIncomeTaxExpenseDetails"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/IncomeTaxesSummaryOfIncomeTaxExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_dc2ecb49-01e6-40d1-81da-806ebd8604de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations_2a5e07e5-137e-42c9-8433-f526c45f1982" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit_dc2ecb49-01e6-40d1-81da-806ebd8604de" xlink:to="loc_us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations_2a5e07e5-137e-42c9-8433-f526c45f1982" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_847c6ea4-0456-40ac-9589-1045a6a14cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit_dc2ecb49-01e6-40d1-81da-806ebd8604de" xlink:to="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_847c6ea4-0456-40ac-9589-1045a6a14cb8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations_5d46d625-c7fb-49e9-ad01-90c5d9ce459c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit_dc2ecb49-01e6-40d1-81da-806ebd8604de" xlink:to="loc_us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations_5d46d625-c7fb-49e9-ad01-90c5d9ce459c" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.orasure.com/role/BusinessCombinationsSummaryofPreliminaryEstimatedFairValuesofAssetsAcquiredandLiabilitiesAssumedDetail" xlink:type="simple" xlink:href="osur-20250930.xsd#BusinessCombinationsSummaryofPreliminaryEstimatedFairValuesofAssetsAcquiredandLiabilitiesAssumedDetail"/>
  <link:calculationLink xlink:role="http://www.orasure.com/role/BusinessCombinationsSummaryofPreliminaryEstimatedFairValuesofAssetsAcquiredandLiabilitiesAssumedDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_7906b0de-a0c6-457e-8c59-205d0b72e2ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_75f6f5e5-78fc-40fa-92eb-59bbe7277627" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_7906b0de-a0c6-457e-8c59-205d0b72e2ad" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_75f6f5e5-78fc-40fa-92eb-59bbe7277627" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_af26cb40-7348-4a49-b53d-caaa04f470fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_7906b0de-a0c6-457e-8c59-205d0b72e2ad" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_af26cb40-7348-4a49-b53d-caaa04f470fd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_d4a19737-23f4-448c-a61d-3c66a621a3c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_d4a19737-23f4-448c-a61d-3c66a621a3c9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_9cdceb1c-4997-4373-8b08-8ae4b29a5065" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_9cdceb1c-4997-4373-8b08-8ae4b29a5065" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_d419e867-9023-47d3-929b-d79b2982ba07" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_us-gaap_Goodwill_d419e867-9023-47d3-929b-d79b2982ba07" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_82a7ae82-ca16-49bb-9ec2-6ad763783ccc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_82a7ae82-ca16-49bb-9ec2-6ad763783ccc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_cf6a8119-3472-4b08-9e83-d91772519452" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_cf6a8119-3472-4b08-9e83-d91772519452" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_osur_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingRightOfUseAssets_522e11cf-c4eb-4be1-bba2-eacb723a256c" xlink:href="osur-20250930.xsd#osur_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingRightOfUseAssets"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_4570b30e-3ca0-4eda-979b-6bab600c5593" xlink:to="loc_osur_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingRightOfUseAssets_522e11cf-c4eb-4be1-bba2-eacb723a256c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_daa456f4-3288-4b44-8a17-432ba3dc4e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_51192821-4f16-488d-a7a6-debcccf43d42" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_daa456f4-3288-4b44-8a17-432ba3dc4e6d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_51192821-4f16-488d-a7a6-debcccf43d42" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_502da969-c11b-4e68-a308-c8660170ae42" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_daa456f4-3288-4b44-8a17-432ba3dc4e6d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_502da969-c11b-4e68-a308-c8660170ae42" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_10b3d2e4-ebc8-469c-a30b-8fa32a24b9b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_daa456f4-3288-4b44-8a17-432ba3dc4e6d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_10b3d2e4-ebc8-469c-a30b-8fa32a24b9b0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_c14f0903-9d87-4b2f-a13b-80b548ab6074" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_daa456f4-3288-4b44-8a17-432ba3dc4e6d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_c14f0903-9d87-4b2f-a13b-80b548ab6074" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
