A synthetic circular peptide containing citrulline called CCP IgG (cyclic citrullinated peptide) has been found to be better at discriminating Rheumatoid Arthritis patients from patients with other diseases such as hepatitis C infection. Rheumatoid Arthritis Classification Criteria include CCP IgG Antibody, rheumatoid factor, C-reactive protein and erythrocyte sedimentation rate (ESR). Approximately 70% of patients with Rheumatoid Arthritis are positive for Anti-CCP IgG, while only about 2% of random blood donors and disease controls subjects are positive.
