Anti-cyclic citrullinated antibodies: complementary to IgM rheumatoid factor in the early diagnosis of rheumatoid arthritis.

Objective: To compare the diagnostic sensitivity of anti-cyclic citrullinated (CCP) antibodies and rheumatoid factor (RF) in rheumatoid arthritis (RA) within a general hospital setting.

Methods: Using the American College of Rheumatology (ACR) classification criteria as a gold standard, the frequency of RF and anti-CCP antibody positivity was compared between two groups of RA patients: those with disease duration less than 2 years (early RA, ERA) and those with disease duration more than 2 years (late RA, LRA).

Results: In ERA, the diagnostic sensitivity of RF and anti-CCP antibodies was 57% and 79% respectively. In LRA, it was 81% and 84% respectively.

Conclusions: Anti-CCP antibodies are 20% more sensitivity than RF in the diagnosis of early RA.