The diagnostic performances of the anti-MCV and the anti-CCP2 tests were similar in the consecutive cohort that included 49 patients with RA (29.9% out of all patients with RA) and 223 patients with non-RA (73.6% out of all patients with non-RA) compared with the total cohort, with a calculated AUC of 0.809 (0.725–0.893) for the anti-MCV ELISA and 0.843 (0.765–0.922) for the anti-CCP2 test. The gene discussed is AGBL2; the disease is rheumatoid arthritis.