Table of Contents
What is a CCP antibody test?
A CCP antibody test detects anti-cyclic citrullinated peptide (anti-CCP) antibodies in the blood. These antibodies are autoantibodies, meaning they are produced by the immune system but mistakenly target the body’s own healthy tissues.
Anti-CCP antibodies primarily target tissues in the joints. Their presence in the blood may indicate rheumatoid arthritis (RA), an autoimmune disease that causes joint pain, swelling, stiffness, and progressive loss of joint function.
Anti-CCP antibodies are present in most people with rheumatoid arthritis and are rarely detected in people without the disease.
Other names: cyclic citrullinated peptide antibody, anticitrullinated peptide antibody, citrulline antibody, anti-cyclic citrullinated peptide, anti-CCP antibody, and ACPA.
What is the test used for?
The CCP antibody test is used to help diagnose or rule out rheumatoid arthritis.
It is commonly performed along with, or after, a rheumatoid factor (RF) test. RF can occur in other autoimmune diseases and may also be present in some healthy individuals. Conversely, some patients with rheumatoid arthritis have little or no RF. Therefore, using both anti-CCP and RF results can provide greater diagnostic accuracy than RF testing alone.
Why might a CCP antibody test be needed?
The test may be considered in patients with symptoms suggestive of rheumatoid arthritis, including:
- Joint pain
- Joint stiffness, particularly in the morning
- Joint swelling
- Fatigue
- Low-grade fever
It may also be performed when other investigations have not confirmed or excluded rheumatoid arthritis.
How is the test performed?
A healthcare professional collects a blood sample from a vein in the arm using a small needle. A small amount of blood is placed into a test tube or vial.
The procedure usually takes less than five minutes. There may be a brief stinging sensation when the needle is inserted or removed.
Is any preparation required?
Inform your healthcare provider about all medicines, vitamins, and dietary supplements you are taking. Depending on the test and laboratory instructions, you may be asked to stop certain substances for approximately 8 hours before testing.
Are there any risks?
There is very little risk associated with a blood test. Mild pain or bruising may occur at the needle-insertion site, but these effects generally resolve quickly.
What do the results mean?
A positive result indicates that anti-CCP antibodies were detected in the blood, whereas a negative result means that they were not detected.
The significance of the result should be interpreted together with the patient’s symptoms, physical examination, RF results, and other investigations.
In a patient with symptoms suggestive of rheumatoid arthritis:
- Anti-CCP positive + RF positive: rheumatoid arthritis is likely.
- Anti-CCP positive + RF negative: may indicate early rheumatoid arthritis or an increased likelihood of developing rheumatoid arthritis in the future.
- Anti-CCP negative + RF negative: rheumatoid arthritis is less likely, although additional evaluation may be required to determine the cause of symptoms.
Anti-CCP antibodies may occasionally be detected in other conditions, including:
- Other autoimmune diseases, such as Sjögren syndrome or systemic lupus erythematosus
- Active tuberculosis
- Chronic lung disease
Therefore, CCP antibody results should always be interpreted in the context of the patient’s clinical history, examination findings, and other investigations.
Other investigations in suspected rheumatoid arthritis
Because rheumatoid arthritis can be difficult to diagnose, particularly during its early stages, additional investigations may be required. These can include:
- Rheumatoid factor (RF)
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Antinuclear antibody (ANA)
- Synovial fluid analysis
- Joint X-rays
ESR and CRP may demonstrate evidence of systemic inflammation, which can support the clinical assessment but are not specific for rheumatoid arthritis.
Key point: Anti-CCP testing is an important laboratory tool in the evaluation of suspected rheumatoid arthritis, but the result should not be interpreted in isolation.
