Comparison of the second and third generation anti-cyclic citrullinated peptide antibody assays in the diagnosis of Japanese patients with rheumatoid arthritis.

The anti-cyclic citrullinated peptide (CCP) antibody has become increasingly important in the diagnosis of rheumatoid arthritis (RA), especially for early diagnosis. The purpose of this study is to compare the diagnostic usefulness of the second and third generation anti-CCP antibody kits among Japanese patients with RA. Anti-CCP antibody titers were measured with the second generation (MESACUP CCP test, Medical and biological laboratories) and third generation (QUANTA Lite CCP3 IgG ELISA, Inova Diagnostics) kits using serum samples from 106 rheumatoid arthritis (RA) patients and 57 non-RA patients. Sensitivities and specificities were compared. The sensitivity and specificity of the second generation anti-CCP (anti-CCP2) kit were 88.7 and 89.5%, and those of the third generation anti-CCP (anti-CCP3) kit were 91.5 and 87.7%. Area under the receiver operating curve showed that anti-CCP2 and anti-CCP3 had similar diagnostic performances. Diagnostic performance of the anti-CCP3 assay was comparable with the anti-CCP2 assay in Japanese patients with RA.