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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 iwfdSUz6ZnisePp3uJyegQ==

<SEC-DOCUMENT>0001104659-10-053490.txt : 20101025
<SEC-HEADER>0001104659-10-053490.hdr.sgml : 20101025
<ACCEPTANCE-DATETIME>20101025154103
ACCESSION NUMBER:		0001104659-10-053490
CONFORMED SUBMISSION TYPE:	D
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
FILED AS OF DATE:		20101025
DATE AS OF CHANGE:		20101025
EFFECTIVENESS DATE:		20101025

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EXAGEN DIAGNOSTICS INC
		CENTRAL INDEX KEY:			0001274737
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		D
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	021-149543
		FILM NUMBER:		101139863

	BUSINESS ADDRESS:	
		STREET 1:		801 UNIVERSITY SE
		STREET 2:		SUITE 209
		CITY:			ALBUQUERQUE
		STATE:			NM
		ZIP:			87106
		BUSINESS PHONE:		505-272-7966

	MAIL ADDRESS:	
		STREET 1:		801 UNIVERSITY BLVD. SE
		CITY:			ALBUQUERQUE
		STATE:			NM
		ZIP:			87106
</SEC-HEADER>
<DOCUMENT>
<TYPE>D
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0704</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001274737</cik>
        <entityName>EXAGEN DIAGNOSTICS INC</entityName>
        <issuerAddress>
            <street1>801 University Blvd SE, Suite 103</street1>
            <city>Albuquerque</city>
            <stateOrCountry>NM</stateOrCountry>
            <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
            <zipCode>87106</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>505-272-7966</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Corporation</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Scott</firstName>
                <middleName>L.</middleName>
                <lastName>Glenn</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd. SE, Suite 103</street1>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Wendy</firstName>
                <lastName>Swedick</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd. SE, Suite 103</street1>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Brian</firstName>
                <lastName>Birk</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>301 Griffin Street</street1>
                <city>Santa Fe</city>
                <stateOrCountry>NM</stateOrCountry>
                <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
                <zipCode>87501</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Dinesh</firstName>
                <lastName>Patel</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>2795 E. Cottonwood Pkwy, Suite 360</street1>
                <city>Salt Lake City</city>
                <stateOrCountry>UT</stateOrCountry>
                <stateOrCountryDescription>UTAH</stateOrCountryDescription>
                <zipCode>84121</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Stephanie</firstName>
                <lastName>Spong</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>301 Griffin Street</street1>
                <city>Santa Fe</city>
                <stateOrCountry>NM</stateOrCountry>
                <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
                <zipCode>87501</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Waneta</firstName>
                <middleName>C.</middleName>
                <lastName>Tuttle</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd. SE, Suite 307</street1>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <stateOrCountryDescription>NEW MEXICO</stateOrCountryDescription>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Michael</firstName>
                <middleName>J.</middleName>
                <lastName>Walsh</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>P.O. Box 3125</street1>
                <city>Del Mar</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>92014</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Biotechnology</industryGroupType>
        </industryGroup>
        <issuerSize>
            <revenueRange>$1 - $1,000,000</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>false</isAmendment>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2010-10-06</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>false</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isEquityType>true</isEquityType>
            <isOptionToAcquireType>true</isOptionToAcquireType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>3548404</totalOfferingAmount>
            <totalAmountSold>1999995</totalAmountSold>
            <totalRemaining>1548409</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>10</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>710000</dollarAmount>
                <isEstimate>true</isEstimate>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>Exagen Diagnostics Inc</issuerName>
                <signatureName>/s/ Wendy Swedick</signatureName>
                <nameOfSigner>Wendy Swedick</nameOfSigner>
                <signatureTitle>Chief Financial Officer</signatureTitle>
                <signatureDate>2010-10-25</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----