0001274737 2023-01-23 2023-01-23 0001274737 false --12-31 8-K 2023-01-23 EXAGEN INC. DE 001-39049 20-0434866 1261 Liberty Way Vista CA 92081 760 560-1501 false false false false Common Stock, par value $0.001 per share XGN NASDAQ true false 2023-01-23