Inflammation and immunity
Anti-CCP
Antibodies that are fairly specific for rheumatoid arthritis; support the diagnosis when joints are inflamed.
Everything about this testWhat it measures
Anti-CCP are autoantibodies against proteins to which the body has attached the substance citrulline (cyclic citrullinated peptides). These antibodies mainly go with rheumatoid arthritis (RA), a chronic inflammation of joints caused by the body's own immune system. The test measures how many of these antibodies are in the blood; the higher the value, the greater the chance of RA. The antibodies can be present years before the first symptoms.
- Rheumatoid arthritis (RA), including at an early stage
- An increased chance of developing joint inflammation in someone who already has joint symptoms
High
A raised anti-CCP fits rheumatoid arthritis if there is also joint inflammation: painful, swollen or warm joints, usually on both sides of the body, with stiffness that is worst in the morning. The higher the value, the greater the chance of RA. Without joint inflammation, a raised value is not a diagnosis: up to 5 in 100 healthy people have rheumatoid factor and/or anti-CCP without RA. In people who do have RA, a positive anti-CCP is linked to a less favorable course, such as a greater chance of joint damage.
Low
A value below the laboratory's cut-off is the normal result. A negative anti-CCP does not rule out rheumatoid arthritis: in about half of people with early RA, the test is negative. In that case, rheumatoid factor may still be positive. Whether there is RA is judged by a doctor mainly from the joints themselves, together with the symptoms and inflammation markers.
If your result is abnormal
With inflamed joints, the GP usually refers you promptly to a rheumatologist, even if anti-CCP is negative, because early treatment limits joint damage. The rheumatologist assesses the result together with the physical examination, the inflammation markers and sometimes imaging. With a raised value without joint inflammation, no treatment follows.
Reliability
According to the Dutch Society for Clinical Chemistry (NVKC), anti-CCP is about as sensitive as rheumatoid factor, but much more specific for rheumatoid arthritis. The Dutch guideline on rheumatoid arthritis advises measuring anti-CCP and rheumatoid factor together when RA is suspected, with anti-CCP being the better predictor of the diagnosis. The NVKC advises against doing the test when the chance of RA is small, certainly not if there is no joint inflammation: screening people without joint symptoms mainly produces false-positive results. The test should not be used to monitor disease activity.
Limitations
- Up to 5 in 100 healthy people have rheumatoid factor and/or anti-CCP without rheumatoid arthritis.
- About half of people with early RA have no detectable anti-CCP.
- Test methods and cut-off values differ per laboratory; values from different labs cannot simply be compared.
- The level of the value says little about how active the disease is during treatment.
How common is this
Rheumatoid arthritis occurs in about 0.5 to 1 in 100 people. Each year, about 3 in 10,000 people are diagnosed. RA occurs at all ages and more often in women than in men.
Who is this useful for
Useful with joints that are swollen, warm or painful and stiff in the morning, especially in the hands, wrists or feet, when a doctor is considering rheumatoid arthritis. According to the Dutch Society for Clinical Chemistry (NVKC), the test is pointless in people without joint symptoms: there is no treatment that prevents RA, and a positive result is then usually false-positive. With joint pain without signs of inflammation, the yield is also small.
Downsides and risks
- A raised anti-CCP without joint inflammation can cause long-lasting worry, while there is no treatment that prevents rheumatoid arthritis.
- A negative result can give false reassurance while the joints are in fact inflamed.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results