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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e6b19-7785-7300-8ae6-f6dc5521462d,g:6bb602cd-be45-43fc-a6e2-adc9d8b7ae2a-->
<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.exagen.com/role/Cover" xlink:type="simple" xlink:href="exdx-20260804.xsd#Cover"/>
  <link:presentationLink xlink:role="http://www.exagen.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019e6b19-7785-7076-9294-fa5c9d7a9c54" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_DocumentType_019e6b19-7785-7076-9294-fa5c9d7a9c54" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019e6b19-7785-7dc0-9bb9-c6d655efb829" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_DocumentPeriodEndDate_019e6b19-7785-7dc0-9bb9-c6d655efb829" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019e6b19-7785-7f13-b050-c62336807845" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityRegistrantName_019e6b19-7785-7f13-b050-c62336807845" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019e6b19-7785-7f55-a2d0-4a636b6296a7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019e6b19-7785-7f55-a2d0-4a636b6296a7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019e6b19-7785-743d-9b6e-80ecf8436261" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityFileNumber_019e6b19-7785-743d-9b6e-80ecf8436261" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019e6b19-7785-7af4-847b-8b1163d10c69" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityTaxIdentificationNumber_019e6b19-7785-7af4-847b-8b1163d10c69" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019e6b19-7785-7e3f-8f10-52fae01d066c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityAddressAddressLine1_019e6b19-7785-7e3f-8f10-52fae01d066c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019e6b19-7785-7558-97bf-60e324ce7262" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityAddressCityOrTown_019e6b19-7785-7558-97bf-60e324ce7262" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019e6b19-7785-74db-8933-5a98d37c6376" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityAddressStateOrProvince_019e6b19-7785-74db-8933-5a98d37c6376" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019e6b19-7785-7957-806b-9b680ae4d00f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityAddressPostalZipCode_019e6b19-7785-7957-806b-9b680ae4d00f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019e6b19-7785-7b9f-9999-a74e759b61be" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_CityAreaCode_019e6b19-7785-7b9f-9999-a74e759b61be" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019e6b19-7785-7d8a-880a-935b7fa2f389" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_LocalPhoneNumber_019e6b19-7785-7d8a-880a-935b7fa2f389" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019e6b19-7785-7b09-9a75-259cea05d475" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_WrittenCommunications_019e6b19-7785-7b09-9a75-259cea05d475" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019e6b19-7785-7f24-91e4-0e0f82284868" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_SolicitingMaterial_019e6b19-7785-7f24-91e4-0e0f82284868" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019e6b19-7785-7da7-bd16-f2607f760745" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_PreCommencementTenderOffer_019e6b19-7785-7da7-bd16-f2607f760745" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019e6b19-7785-724e-a91a-36d869f29086" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019e6b19-7785-724e-a91a-36d869f29086" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e6b19-7785-7404-9c28-2c9fc98f5354" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_Security12bTitle_019e6b19-7785-7404-9c28-2c9fc98f5354" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e6b19-7785-74d3-91fe-789eb09a518c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_TradingSymbol_019e6b19-7785-74d3-91fe-789eb09a518c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e6b19-7785-7194-acb2-8b1708ee42b1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_SecurityExchangeName_019e6b19-7785-7194-acb2-8b1708ee42b1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019e6b19-7785-7a3d-b61a-6e2c1f9941d4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityEmergingGrowthCompany_019e6b19-7785-7a3d-b61a-6e2c1f9941d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019e6b19-7785-70d2-803e-165854421a30" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_EntityCentralIndexKey_019e6b19-7785-70d2-803e-165854421a30" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019e6b19-7785-7577-8cd8-60acb7bec5ca" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019e6b19-7785-709f-896d-32c432ff86cf" xlink:to="loc_dei_AmendmentFlag_019e6b19-7785-7577-8cd8-60acb7bec5ca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>
