Cyclic Citrullinated Peptide Antibody Blood Test
Last updated April 27, 2018
Approved by: Maulik P. Purohit MD, MPH

The Citrullinated Peptide Antibody Blood Test is a test to detect citrullinated peptide antibodies in blood. It is a sensitive test that is used as a marker for rheumatoid arthritis, and to assess its severity.
What are the other Names for this Test? (Equivalent Terms)
- ACPA Blood Test
- Anti-CCP Blood Test
- Anti-Cyclic Citrullinated Peptide Blood Test
What is Cyclic Citrullinated Peptide Antibody Blood Test? (Background Information)
- Citrulline is an intermediate that is required in the excretion of ammonia, as urea. The conversion of ammonia to urea occurs in the kidneys, through a process known as the urea cycle
- Citrulline can also be made from the amino acid arginine, on-site, within a protein. Since, in any case, proteins are made up of amino acids, such as arginine. This results in a modification of the protein’s structure and activity. This is an example of a post-translational modification, because it occurs after translation, or conversion from RNA
- Various enzymes and DNA-coiling proteins are post-translationally modified (part of protein biosynthesis). Post-translational modification allows for their activity to be fine-tuned relatively quickly. For example, DNA-coiling proteins known as histones, wrap DNA around themselves, to compact it. This allows for the packaging of millions of miles of DNA into a tiny nucleus within the cell
- Histones contain tails that can be post-translationally modified. Citrullination of a histone has been shown to loosen its hold on DNA and allow processing machinery to access it. This results in the expression of that region of DNA to protein
- The conversion of arginine to citrulline may enable interactions with neighboring amino acids that result in the formation of a ring structure. This kind of protein is called a cyclic citrullinated peptide
- In certain cases, the body may form autoantibodies against this structure. Autoantibodies are problematic antibodies that target the body’s own tissues. They are responsible for causing autoimmune disorders, such as rheumatoid arthritis
- The Citrullinated Peptide Antibody Blood Test is a test to detect citrullinated peptide antibodies in blood. It is a sensitive test that is used as a marker for rheumatoid arthritis, and to assess its severity
What are the Clinical Indications for performing the Cyclic Citrullinated Peptide Antibody Blood Test?
Following are the clinical indications for performing the Cyclic Citrullinated Peptide Antibody Blood Test:
- Evaluate the severity of rheumatoid arthritis
- Joint problems, including:
- Stiffness
- Pain
- Inflammation
- Lumps
- Fatigue
- Fever
How is the Specimen Collected for Cyclic Citrullinated Peptide Antibody Blood Test?
Following is the specimen collection process for Cyclic Citrullinated Peptide Antibody Blood Test:
Sample required: Blood
Process: Insertion of a needle into an arm vein.
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Cyclic Citrullinated Peptide Antibody Blood Test Result?
- A positive Cyclic Citrullinated Peptide Antibody Blood Test may indicate rheumatoid arthritis
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- The Cyclic Citrullinated Peptide Antibody Blood Test may be performed alongside other imaging tests, such as an x-ray, to gain better understanding of the clinical scenario
- The blood test is often performed alongside a rheumatoid factor test, or a RF test
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.