Anti-CCP Anti-Cyclic Citrullinated Peptide Antibody:
Rheumatoid arthritis is both common and chronic symptoms, with significant consequences for multiple organ systems. Better understanding of its pathophysiology has led to the development of targeted therapies that have dramatically improved outcomes. The key to therapeutic success lies in identifying individuals who will have severe destructive disease as early as possible, so that effective treatment can be initiated before irreversible damage occurs. Anti-cyclic citrullinated peptide (anti-CCP) antibody testing is particularly useful in the diagnosis of rheumatoid arthritis, with high specificity, presence early in the disease process, and ability to identify patients who are likely to have severe disease and irreversible damage.
What is a CCP antibody test?
What is it used for?
Anti CCP antibody test is used to help diagnose rheumatoid arthritis. It’s often done along with or after a rheumatoid factor (RF) test. Rheumatoid factors are another type of autoantibody. RF tests used to be the main test to help diagnose rheumatoid arthritis. But RF factors can be found in people with other autoimmune diseases and even in some healthy people. Many studies have shown that CCP antibodies provide a more accurate diagnosis of rheumatoid arthritis compared with RF testing. Anti-CCP antibody assay is prescribed at the same time as or following an RA test (see this section) if a person shows signs or symptoms suggesting inflammatory arthritis. Signs and symptoms may include the following:
Why do I need a CCP antibody test?
You may need this test if you have symptoms of rheumatoid arthritis. These include:
- Joint Pain
- Joint stiffness, especially in the morning
- Joint swelling
- Painful, hot and/or swollen joints, most often in the hands and wrists
- Occasional pain in the elbows, neck, shoulders, hips, knees and feet
- Stiffness in the joints when getting up in the morning, which decreases during the day
- Fatigue and fever
- The development of nodules under the skin, especially at the elbows
- A general feeling of discomfort
What does the test measure?
The cyclic citrullinated peptide antibody test identifies CCP antibodies in the blood. CCP antibodies are a specific type of antibody produced by the immune system called an autoantibody.
While most antibodies help the body fight disease by recognizing and neutralizing foreign substances like bacteria and viruses, autoantibodies don’t fulfill this important immune function. Instead, autoantibodies can act abnormally by targeting and attacking the body’s healthy cells and tissues.
CCP antibodies are detected in most patients with rheumatoid arthritis. Although less common, CCP antibodies may be detected in other autoimmune disorders, including Sjogren’s syndrome and lupus. Positive results for CCP antibodies can also occur in patients with active tuberculosis (TB) and in some patients with chronic lung disease
What do the results mean?
Positive anti-CCP test + positive RA test:
Have signs or symptoms of arthritis, positive results in both the anti-CCP and RA tests are highly predictive of rheumatoid arthritis and you may develop a more progressive and severe form.
Positive anti-CCP test + negative RA test
Slightly positive anti-CCP test + slightly positive RA test
You have suggestive signs of rheumatoid arthritis and positive results in the anti-CCP test but negative results in the RA test, or if you are symptomatic with weak results in both tests, it is likely that you are in the early phase of the disease or that it will develop in the future.
Negative anti-CCP test + positive RA test
If you have negative results in the anti-CCP test but positive results in the RA test, the symptoms and clinical signs will determine the diagnosis for the disease.
Negative anti-CCP test + negative RA test
Your results are negative for both tests (anti-CCP and RA), it is likely that the arthritis is due to a cause other than rheumatoid arthritis.
How Sensitive and Specific Is the Anti-CCP Test?
For rheumatoid arthritis, anti-CCP is not particularly sensitive — just 50 to 75 percent, depending on the study you look at. This means that around two-thirds of negative results would be “true negatives” (no RA diagnosis), but around a third of people with negative results actually might have RA after all. (More on this, which is known as seronegative rheumatoid arthritis, below.)
On the other hand, the CCP test is more than 90 percent specific, which means that less than 10 percent of people who test positive do not meet the criteria for rheumatoid arthritis. If you test positive for anti-CCP, it’s a good indication you likely have rheumatoid arthritis.
Citrullination is a normal physiologic process that occurs in many dying cells.  Citrulline is a nonstandard amino acid that is produced by diminution of arginine residue present on certain human proteins by the peptidyl arginine-deiminase (PAD) enzyme. The PAD enzyme has several isoforms, of which PAD2 and PAD4 are expressed in inflammatory leukocytes.  The release of PAD from dying cells citrullinates extracellular proteins that contain arginine. Production of anti–citrullinated protein antibody (ACPA) depends on the genetic background of the patient.
- < 20 EU/mL – Negative What Diseases Does the Anti-CCP Test Help Rule Out? If the anti-CCP test comes back positive, a rheumatologist can likely rule out types of inflammatory arthritis that are considered to be seronegative, such as psoriatic arthritis and ankylosing spondylitis, says Dr. Kaplan. That said, even a positive anti-CCP test isn’t totally conclusive for rheumatoid arthritis. “Even though the anti-CCP is considered fairly specific for rheumatoid arthritis, you can see it sometimes in a small percentage of patients with other types of inflammatory arthritis,” says Dr. Kaplan. Positive anti-CCP results have been seen in patients with lupus and Sjogren’s syndrome, for example. Read More