Rheumatoid factor and antibodies to cyclic citrullinated Peptide differentiate rheumatoid arthritis from undifferentiated polyarthritis in patients with early arthritis.

Abstract

The criterion IgM-RF > 40 or anti-CCP > 50 is able to predict the diagnosis of RA in early arthritis patients with high specificity and acceptable sensitivity. Anti-CCP testing combined with IgM-RF testing has additional value over IgM-RF testing alone in patients with early undifferentiated oligo and polyarthritis.