Biorex Anti-cyclic citrullinated peptide antibody (Anti-CCP) is an in-vitro test for the quantitative determination of Anti-CCP in human serum or plasma. The diagnosis of rheumatoid arthritis (RA) often relies on clinical manifestations and laboratory tests as rheumatoid factor and C-reactive protein. However, the identification of citrulline as a target of a whole set of auto-antibodies detected in the sera of RA patients has led to the development of anti-CCP assays (antibody to cyclic citrullinated peptides) which possess a high specificity for RA. The clinical performance of anti-CCP assays has been further improved by the use of multiple citrullinated peptides, resulting in a second generation of anti-CCP assays.