Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO SECTION 906

OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Exagen Inc. (the “Company”) for the quarter ended September 30, 2019, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Fortunato Ron Rocca, the President and Chief Executive Officer, and Kamal Adawi, the Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to his knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company for the periods presented therein.

Dated: November 12, 2019

/s/ Fortunato Ron Rocca	/s/ Kamal Adawi
Fortunato Ron Rocca	Kamal Adawi
President and Chief Executive Officer (Principal Executive Officer)	Chief Financial Officer (Principal Financial Officer)

A signed original of this written statement required by Section 906 has been provided to Exagen Inc. and will be retained by Exagen Inc. and furnished to the Securities and Exchange Commission or its staff upon request. These certifications will not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor will these certifications be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except to the extent that the registrant specifically incorporates them by reference.