-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 AZ116Jd7yRNdR6ghQ/MDIA1L2zYXaj+BW2C16kOcGTJvWD94rVN6ub8D+pP9nnaQ
 rjQgzjSTE2PXg/N+rge7yg==

<SEC-DOCUMENT>0001274737-09-000004.txt : 20090526
<SEC-HEADER>0001274737-09-000004.hdr.sgml : 20090525
<ACCEPTANCE-DATETIME>20090526132216
ACCESSION NUMBER:		0001274737-09-000004
CONFORMED SUBMISSION TYPE:	D
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
FILED AS OF DATE:		20090526
DATE AS OF CHANGE:		20090526
EFFECTIVENESS DATE:		20090526

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:	021-61411
		FILM NUMBER:		09851200

	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>X0301</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001274737</cik>
        <entityName>EXAGEN DIAGNOSTICS INC</entityName>
        <issuerAddress>
            <street1>801 UNIVERSITY SE</street1>
            <street2>SUITE 209</street2>
            <city>ALBUQUERQUE</city>
            <stateOrCountry>NM</stateOrCountry>
            <zipCode>87106</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>505-272-7966</issuerPhoneNumber>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <jurisdictionOfInc>DE</jurisdictionOfInc>
        <entityType>Corporation</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>John</firstName>
                <middleName>P.</middleName>
                <lastName>Alsobrook, II</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd. SE</street1>
                <street2></street2>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Dinesh</firstName>
                <middleName></middleName>
                <lastName>Patel</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>2795 E. Cottonwood Parkway</street1>
                <street2>Suite 360</street2>
                <city>Salt Lake City</city>
                <stateOrCountry>UT</stateOrCountry>
                <zipCode>84121</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>John</firstName>
                <middleName></middleName>
                <lastName>Bessone</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>263 Staab Street</street1>
                <street2></street2>
                <city>Santa Fe</city>
                <stateOrCountry>NM</stateOrCountry>
                <zipCode>87501</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Todd</firstName>
                <middleName></middleName>
                <lastName>Stevens</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One South Main Street</street1>
                <street2>Suite 800</street2>
                <city>Salt Lake City</city>
                <stateOrCountry>UT</stateOrCountry>
                <zipCode>84133</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Brian</firstName>
                <middleName></middleName>
                <lastName>Birk</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>301 Griffin Street</street1>
                <street2></street2>
                <city>Santa Fe</city>
                <stateOrCountry>NM</stateOrCountry>
                <zipCode>87506</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Lisa</firstName>
                <middleName></middleName>
                <lastName>Davis</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd SE</street1>
                <street2>Suite 209</street2>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Waneta</firstName>
                <middleName>C.</middleName>
                <lastName>Tuttle</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>801 University Blvd. SE</street1>
                <street2>Suite 209</street2>
                <city>Albuquerque</city>
                <stateOrCountry>NM</stateOrCountry>
                <zipCode>87106</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </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>2009-05-08</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>2000000</totalOfferingAmount>
            <totalAmountSold>1000000</totalAmountSold>
            <totalRemaining>1000000</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>15</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>340000</dollarAmount>
                <isEstimate>true</isEstimate>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>EXAGEN DIAGNOSTICS INC</issuerName>
                <signatureName>John P. Alsobrook, II</signatureName>
                <nameOfSigner>John P. Alsobrook, II</nameOfSigner>
                <signatureTitle>President and CEO</signatureTitle>
                <signatureDate>2009-05-26</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----