What Is a CCP Antibody Test?
This test detects CCP antibodies in the patient’s blood. CCP antibodies, also known as the anti-cyclic citrullinated peptide antibodies, are a type of antibodies called autoantibodies.
What Are Antibodies and Autoantibodies?
Antibodies and autoantibodies are immune proteins that are generated by the host’s immune system. Antibodies attack foreign antigens like viruses and bacteria that enter the body, whereas autoantibodies attack the body's healthy cells by mistake. Therefore, CCP antibodies are a specific type of antibodies produced by the immune system called an autoantibody that reacts with the self-antigens of the body.
What Are CCP Antibodies?
CCP antibodies are most commonly detected in patients with rheumatoid arthritis. Although less frequently, CCP antibodies may also be detected in other autoimmune disorders such as Sjogren’s syndrome and lupus. CCP antibodies can also be found in the blood samples of patients with active tuberculosis and some patients with chronic lung disease.
CCP antibodies mistakingly target and react with the tissues in the joints of rheumatoid arthritis patients. If CCP antibodies are found in the blood of an individual, it can be a sign of rheumatoid arthritis. Rheumatoid arthritis is an autoimmune disease that causes pain, swelling, and stiffness in and around the joints. CCP antibodies are present in approximately 75 percent of people who have rheumatoid arthritis. They are almost always absent in individuals without the disease.
What Are the Synonyms for the CCP Antibody Test?
Citrulline antibody, cyclic citrullinated peptide antibody, and anti-citrullinated peptide antibody (ACPA).
What Is the Purpose of This Test?
The main aim of the CCP antibody test is to look for CCP antibodies in the blood. The antibody testing is critical for diagnosing rheumatoid arthritis and assessing its potential severity:
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Diagnosing Rheumatoid Arthritis: CCP antibody testing is used to help diagnose or rule out rheumatoid arthritis in patients showing symptoms. There is no specific single test for rheumatoid arthritis. Hence, CCP antibody testing is considered an adjunctive test that will help prioritize the diagnosis of rheumatoid arthritis cases.
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Estimating Severity of the Disease: The progression of a patient’s rheumatoid arthritis can be predicted by the CCP antibody test. This will aid the clinicians in identifying the course of the disease. Early rheumatoid arthritis patients who test positive for CCP antibodies are at a higher risk of worsening joint damage.
What Does the CCP Antibody Test Measure?
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Potential Predictive Value of Anti-CCP Antibodies - This value is required to detect individuals who are at an increased risk of developing rheumatoid arthritis. Ideally, screening of individuals from families who have a genetic tendency to develop rheumatoid arthritis should be done for the CCP antibody test. The CCP antibody test is very useful for patients who are at a higher risk for developing progressive rheumatoid arthritis since they will benefit most from early aggressive intervention.
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Positive Correlation with Other Disease Parameters - Anti-CCP antibodies correlates with other important parameters of the disease activity. It has been found that anti-CCP antibodies show a positive correlation with a higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), swollen joint count, and deteriorating clinician global assessment ratings in rheumatoid arthritis cases. However, other tests like the rheumatoid factor, which is also carried out as an adjunctive test in rheumatoid arthritis patients, were found to be positively correlated with increased ESR (erythrocyte sedimentation rate) and CRP (C-Reactive protein), but there was no association with other disease activity markers. Therefore, the CCP antibody test is an important test to identify the diagnosis and severity of the patients suffering from rheumatoid arthritis.
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Assess the Damage Caused- In addition to disease activity, irreversible damage caused by rheumatoid arthritis poses a significant impact on the quality of life and functional capability of individuals. It is difficult to predict which patients will cause damage, and disease activity parameters are not always accurate in predicting the worsening destruction of the joints. Anti-CCP antibodies help in identifying patients who are at an increased risk of damage and who would not have been identified using the rheumatoid factor test alone.
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Anti-CCP Titers - The anti-CCP titers change with treatment. It has been found that the anti-CCP titers decrease following successful rheumatoid arthritis treatment. It can therefore be summarized that a decrease in anti-CCP antibodies can be seen with rheumatoid arthritis treatment. However, the decrease should not drive treatment decisions.
When Should a CCP (Cyclic Citrullinated Peptide) Antibody Test Be Done?
The CCP antibody test should be done on the doctor’s recommendation if patients experience signs or symptoms of rheumatoid arthritis. Symptoms of rheumatoid arthritis include:
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Severe joint pain both at rest and at work.
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Joints may feel warm, tender, painful, swollen, and inflamed.
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Morning stiffness and stiffness post resting, usually lasting over thirty minutes, are other common symptoms experienced by the patients.
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Tiredness.
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Intermittent low-grade fevers.
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Loss of appetite and weakness.
If a combination of these symptoms is being experienced by the patient, the doctor may ask him to get the CCP antibody test done.
What Is the Biological Principle of the CCP Antibody Test?
The Anti-CCP test is a two-step immunoassay for the semi-quantitative determination of the IgG autoantibodies specific to a cyclic citrullinated peptide (CCP) in human serum or plasma.
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In the first step, the sample is pre-diluted with a wash buffer, after which the pre-diluted sample, CCP-coated paramagnetic microparticles, and sample diluent combine. The sample contains the anti-CCP antibodies that bind to the CCP-coated microparticles absorbed on the microplate.
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After washing, the second step comprises the addition of anti-human IgG acridinium-labeled conjugate. After the wash cycle, the trigger solutions are added to the reaction mixture. The chemiluminescent reaction that follows is measured as relative light units (RLUs).
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The amount of anti-CCP antibodies in the sample and the RLUs detected by the system optics are directly proportional.
How to Get Tested for CCP Antibody Test?
A health care provider will take a blood sample from a vein in your arm. A little sting may be felt when the needle goes in or out of the patient. Collected blood samples are then sent to a laboratory for detection and measurement of CCP antibodies.
What Do the CCP (Cyclic Citrullinated Peptide) Antibody Test Results Suggest?
If the CCP antibody test results of the patient are positive, it means the autoantibodies were found in the blood. A negative test result is suggestive of no CCP antibodies in the patient’s blood sample. The following inference can be made from the test results if the patient is suffering from rheumatoid arthritis-
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Positive CCP antibodies, along with positive RF (rheumatoid factor), are suggestive of rheumatoid arthritis.
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Positive CCP antibodies with negative RF (rheumatoid factor) may mean the patient is in the early stages of rheumatoid arthritis or may develop it in the future.
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Negative CCP antibodies and negative RF (rheumatoid factor) mean the patient is not likely to have rheumatoid arthritis. More tests are needed to be done to diagnose the disease.
Conclusion
Rheumatoid arthritis is a chronic disease with significant consequences for multiple organ systems. The key to the therapeutic approach lies in identifying individuals who will have the destructive disease as early as possible so that treatment modality can be initiated before irreversible destruction occurs. Anti-cyclic citrullinated peptide (anti-CCP) antibody testing is found to be particularly useful in ruling out rheumatoid arthritis, with high specificity and identifying patients who are likely to have severe disease and irreversible damage. However, the sensitivity of the test is low, and a negative result does not completely exclude the disease.
