Anti CCP (Cyclic Citrullinated Peptide)
1. What is Anti CCP?
Antibodies to Cyclic Citrullinated Peptide. These are autoantibodies produced by the immune system that are directed against cyclic citrullinated peptides (CCP). Citrulline is naturally produced in the body as part of the metabolism of the amino acid arginine. However, in joints with rheumatoid arthritis (RA), this conversion may occur at a higher rate. Citrulline changes the protein structure and can trigger an immune response, producing autoantibodies against joint proteins, thereby causing joint damage and erosion.
2. What is the use of doing Anti CCP?It is done to aid in the diagnosis of Rheumatoid Arthritis (RA). The 2010 Rheumatoid Arthritis Classification Criteria from the American College of Rheumatology (ACR) includes CCP antibody testing, along with RF, as part of its criteria for diagnosing rheumatoid arthritis.
3. What is Rheumatoid arthritis?RA is a chronic, systemic autoimmune disease that causes inflammation, pain, stiffness, and destructive changes in the hands, feet, and other joints throughout the body. It can affect anyone at any age, but it usually develops between the ages of 40 and 60, and about 75% of those affected are women. The course of RA and its prognosis are variable. It may develop and progress slowly or rapidly. It may go into remission in some people and, in a few, it may go away. Left untreated, RA can shorten a person's lifespan and can, within a few years, leave many of those affected too disabled to work.
4. When is this test done?➢ Joint pain/ inflammation / stiffness ➢ Rheumatoid factor test is positive. In this case, it is done for confirmation. ➢ Inflammatory markers such as ESR, CRP are high. ➢ Suspicion of Rheumatoid arthritis
5. What are the advantages of this test?➢ Early diagnosis of RA- There are a variety of treatments available to minimize the complications of RA, but they depend on making an accurate diagnosis and on beginning treatment before the development of significant joint damage. ➢ Rheumatoid factor (RF) has been the primary blood test used to detect RA and distinguish it from other types of arthritis and other inflammatory processes. However, the sensitivity and specificity of RF are not ideal; it can be negative in people who have clinical signs of RA and positive in people who do not. Studies have shown that the CCP antibody test has a sensitivity and specificity that is equal to or better than RF and is more likely to be positive with early RA. ➢ According to the ACR, CCP antibodies may be detected in about 50-60% of people with early RA, as early as 3-6 months after the beginning of symptoms. Early detection and diagnosis of RA allows healthcare providers to begin aggressive treatment of the condition, minimizing the associated complications and tissue damage. ➢ CCP antibody testing may also be ordered to help evaluate the likely development of RA in people with undifferentiated arthritis – those whose symptoms suggest but do not yet meet the American College of Rheumatology (ACR) criteria for RA. According to ACR, approximately 95% of those with a positive CCP antibody will meet the criteria of RA in the future. Early detection of RA is essential for guiding treatment decisions.
6. What sample is required?A blood sample is taken for the test. No additional preparation needs to be done.
7. What is the turn-around time (TAT) for the test?The test results are made available the same day.
8. What do the test results mean?➢ When people with signs and symptoms of arthritis are positive for both CCP antibody and RF, it is very likely that they have RA and it is likely that they may develop a more rapidly progressive and severe form of the disease. ➢ When people are positive for CCP antibody but not RF, or have low levels of both, and have clinical signs that suggest RA, then it is likely that they have early RA or that they will develop RA in the future. ➢ When individuals are negative for CCP antibody but have a positive RF, then the clinical signs and symptoms are more vital in determining whether they have RA or some other inflammatory condition. ➢ When someone is negative for both CCP antibody and RF, then it is less likely that the person has RA. However, please note that RA is a clinical diagnosis and may be made in the absence of positive tests for autoantibodies.
9. Does this test become positive in any other conditions?CCP antibodies are rarely found in other autoimmune conditions, such as lupus, Graves disease and Sjogren syndrome, and may be detected in infections such as tuberculosis.
Reference: American Association of Clinical Chemistry