Anti-Cyclic Citrullinated Peptide Antibody (Anti-CCP)
The anti-cyclic citrullinated peptide (anti-CCP) test detects antibodies against citrullinated proteins. It is used mainly to help evaluate rheumatoid arthritis.
Because anti-CCP is more specific for rheumatoid arthritis than rheumatoid factor, so it helps a clinician distinguish RA from other causes of joint symptoms. It can sometimes be positive years before symptoms appear, and it may offer clues about how the condition could progress. It is most informative when read together with RF and your clinical picture.
A positive anti-CCP is strongly associated with rheumatoid arthritis and, in people with RA, higher levels are sometimes linked to more aggressive joint involvement. Because it is fairly specific, a positive result carries meaningful weight, but it is still interpreted alongside symptoms, imaging, and other labs rather than in isolation.
A negative anti-CCP makes rheumatoid arthritis less likely but does not exclude it, since some people with RA test negative. Your clinician considers it together with RF, symptoms, and joint findings.
A negative result is typical. Any positive result should be interpreted by your clinician in the context of your joint symptoms and other rheumatology testing.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.