<SEC-DOCUMENT>0001274737-25-000051.txt : 20250612
<SEC-HEADER>0001274737-25-000051.hdr.sgml : 20250612
<ACCEPTANCE-DATETIME>20250612203207
ACCESSION NUMBER:		0001274737-25-000051
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250610
FILED AS OF DATE:		20250612
DATE AS OF CHANGE:		20250612

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kim Paul
		CENTRAL INDEX KEY:			0001253820
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39049
		FILM NUMBER:		251044519

	MAIL ADDRESS:	
		STREET 1:		4399 SANTA ANITA AVE
		CITY:			EL MONTE
		STATE:			CA
		ZIP:			91731

	FORMER NAME:	
		FORMER CONFORMED NAME:	KIM PAUL
		DATE OF NAME CHANGE:	20030711

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EXAGEN INC.
		CENTRAL INDEX KEY:			0001274737
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MEDICAL LABORATORIES [8071]
		ORGANIZATION NAME:           	08 Industrial Applications and Services
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1261 LIBERTY WAY
		CITY:			VISTA
		STATE:			CA
		ZIP:			92081
		BUSINESS PHONE:		(760) 560-1501

	MAIL ADDRESS:	
		STREET 1:		1261 LIBERTY WAY
		CITY:			VISTA
		STATE:			CA
		ZIP:			92081

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	EXAGEN DIAGNOSTICS INC
		DATE OF NAME CHANGE:	20031230
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>wk-form4a_1749774721.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2025-06-10</periodOfReport>

    <dateOfOriginalSubmission>2025-06-12</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001274737</issuerCik>
        <issuerName>EXAGEN INC.</issuerName>
        <issuerTradingSymbol>XGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253820</rptOwnerCik>
            <rptOwnerName>Kim Paul</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O EXAGEN INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1261 LIBERTY WAY</rptOwnerStreet2>
            <rptOwnerCity>VISTA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92081</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option(right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.36</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-06-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2035-06-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9000</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.</footnote>
        <footnote id="F2">On June 12, 2025, the reporting person filed a Form 4 which inadvertently reported that, following his grant of 9,000 stock options, he beneficially owned 18,000 stock options. In fact, as reported in this amendment, the reporting person beneficially owned 9,000 stock options.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jeffrey G. Black, as attorney-in-fact</signatureName>
        <signatureDate>2025-06-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
