<SEC-DOCUMENT>0001493152-21-003529-index.html : 20210212
<SEC-HEADER>0001493152-21-003529.hdr.sgml : 20210212
<ACCEPTANCE-DATETIME>20210212095129
ACCESSION NUMBER:		0001493152-21-003529
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20210212
DATE AS OF CHANGE:		20210212

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EXAGEN INC.
		CENTRAL INDEX KEY:			0001274737
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MEDICAL LABORATORIES [8071]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-91300
		FILM NUMBER:		21623544

	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

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RTW INVESTMENTS, LP
		CENTRAL INDEX KEY:			0001493215
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		40 10TH AVENUE
		STREET 2:		7TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014
		BUSINESS PHONE:		646-597-6980

	MAIL ADDRESS:	
		STREET 1:		40 10TH AVENUE
		STREET 2:		7TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RTW INVESTMENTS, LLC
		DATE OF NAME CHANGE:	20100602
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>formsc13ga.htm
<TEXT>
Document 1 - file: formsc13ga.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-1
<SEQUENCE>2
<FILENAME>ex1.htm
<TEXT>
Document 2 - file: ex1.htm

</DOCUMENT>
</SEC-DOCUMENT>