What Is the CCP Antibody Test?

The cyclic citrullinated peptide test can help to diagnose rheumatoid arthritis

Updated on January 18, 2023

Medically reviewed by Grant Hughes, MD

The CCP (cyclic citrullinated peptide) test measures CCP antibodies in the blood. These proteins are part of an immune system attack on healthy tissues and cells, such as the joints. A healthcare provider may order this test to help diagnose rheumatoid arthritis (RA).

Another common name for this is the anti-cyclic citrullinated peptide (anti-CCP) test. Other names include:

Citrulline antibody
Cyclic citrullinated peptide antibody
Anticitrullinated peptide antibody (ACPA)

This article explains what citrullinated proteins do and how the CCP test is used to evaluate them. It offers a step-by-step approach to the test, and what high cyclic citrullinated peptide levels and other results mean.

What Do Citrullinated Proteins Do?

Under certain natural conditions, such as inflammation, the body converts the amino acid arginine to the amino acid citrulline. Cyclic citrullinated peptides are circular proteins that contain citrulline.

If a person has rheumatoid arthritis, the joints make an excess of citrulline, which can change the structure of proteins. The immune system recognizes the changes in the proteins and responds by making cyclic citrullinated peptide autoantibodies. Autoantibodies are antibodies that attack a person's healthy tissues and cells.

What Does the CCP Test Measure?

The CCP antibody test is used to check if there are cyclic citrullinated peptide antibodies (Immunoglobulin G, or IgG) in the blood. A healthcare provider orders the test to help determine if a person has RA, since it is possible to measure cyclic citrullinated peptide antibodies in a person's blood with a blood test.

In addition to helping your healthcare provider diagnose RA, a CCP antibody test may also predict the severity of the disease and possible damage. A positive CCP antibody test increases the chances of a person having a more severe form of RA with more joint damage.

The blood test can help identify people who are more likely to have these problems with RA. A healthcare provider may suspect you have RA based on your symptoms such as:

Fatigue
Low-grade fever
Joint pain
Stiffness
Swelling

An estimated 75% of adults with RA have cyclic citrullinated peptide antibodies in their blood. It is rare for someone without rheumatoid arthritis to have CCP antibodies unless they have another autoimmune condition that would cause a similar result.

Another blood test a healthcare provider often orders together with a CCP antibody test is the rheumatoid factor blood test. If both your CCP and rheumatoid factor antibody tests are positive, there is a strong chance you have or will develop RA.

Your healthcare provider may order other blood tests during the RA diagnosis process, including:

You may also have imaging tests to check your joints for damage, such as an X-ray, MRI, or ultrasound scan.

Research has not found what causes RA. However, there are risk factors that increase the chance of someone having this condition, such as specific genes, smoking, and obesity. Other risk factors include being an older adult, though RA can begin at any age.

Risks and Contraindications

The CCP antibody blood test is a low-risk procedure. In general, blood tests have few risks and contraindications, so they are safe for most people. You may have some pain, swelling, or bruising where the needle enters your vein during the blood draw.

Occasionally, a hematoma (swelling of pooled blood) may form under your skin. Some people feel lightheaded, dizzy, or faint during a blood test. Usually, these symptoms go away on their own and do not last for long.

The CCP antibody blood test is generally considered to be accurate and specific when results are positive, indicating RA is likely. However, the antibodies are not present in up to three-fourths of all people at or before a diagnosis, so having a negative test result does not entirely rule out the possibility of RA.

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Before the Test

If your healthcare provider recommends a CCP antibody blood test, you can expect to discuss the possibility that you may have RA at the same appointment. Your healthcare provider may also suggest scheduling other imaging and blood tests to determine an RA diagnosis.

You should tell your healthcare provider about any prescription medications, vitamins, dietary supplements, and over-the-counter drugs you are taking. Your practitioner will determine if you need to stop taking any of them before the test.

How To Prepare for the Test

You do not need to do anything special to prepare for a CCP antibody blood test. You can eat and drink as normal before the test. Your healthcare provider will warn you if you must stop taking certain medications before the test.

Timing

The actual blood draw takes less than five minutes. You may have to wait for your turn, depending on when and where you schedule the appointment.

Location

Where you have the test can vary. You may be able to have the CCP antibody blood test in your healthcare provider's office, laboratory, or hospital. Your practitioner will help you find a convenient location to have the test.

Cost and Insurance

Your health insurance may cover the cost of the CCP antibody test. Contact your insurance company and talk to your healthcare provider to determine if the test is covered. Ask if there are any costs, such as deductibles, that you will have to pay. The price of a CCP antibody blood test can range from $100 to $200.

What to Bring and What to Wear

You do not have to bring anything special to have a blood test. You may need your health insurance information or another payment method with you. If you believe there will be a long wait time before your appointment, bring something to stay occupied, like a book, phone, or tablet.

You can wear what you like to the test since there are no specific clothing requirements. You may feel more comfortable in clothes with short sleeves, so you do not have to roll up the sleeve for the blood draw. However, you can wear long sleeves if you prefer and roll them up.

During the Test

A trained healthcare professional, such as a nurse, laboratory technician, or phlebotomist, will do the blood test.

Pre-Test

You may have to fill out some paperwork and answer questions before the CCP antibody test.

Throughout the Test

The healthcare professional will ask you to sit down in a chair or on an exam table. If you are not wearing short sleeves, you will have to roll up the sleeve on one of your arms. They may tie a band around your arm or ask you to make a fist, so it is easier to find a vein. Usually, they can find a vein inside your arm near the elbow crease.

The healthcare professional will clean the inside of your arm with alcohol to sanitize it. Next, they will insert a small needle into your arm. You may feel some pain, stinging, poking, or pinching. Some people prefer to look away when this is happening. They will collect the blood from a vein in your arm in a test tube or a vial.

They will take off the band around your arm and take out the needle. You may have a piece of gauze, cotton ball, or tissue put on top of the entrance site of the needle. You may have to hold this piece to create pressure to stop bleeding, and a bandage may be placed on top. The test should take less than five minutes.

Post-Test

If you feel dizzy or lightheaded, tell the healthcare professional. You may need to lie down until this passes, or you may want to drink and eat something. When you feel well enough, you may leave as long as the bleeding has stopped.

After the Test

Your blood sample will be analyzed by the laboratory, which will check for the presence of cyclic citrullinated peptide antibodies. You do not need to take any special precautions after the blood test. You should be able to resume normal activities immediately.

If there is a hematoma, pain, soreness, swelling, or bruising in the area where you had the blood draw, it should go away on its own within a couple of days. However, tell your healthcare provider if the symptoms persist or get worse.

Rheumatoid Arthritis Diagnosis

The CCP antibody blood test is one component of diagnosing RA. There is not a single RA test that can give you a definitive diagnosis, so your healthcare provider will order more imaging and blood tests. You may also have a rheumatoid factor (RF) antibody test. If both your CCP and RF antibody tests are positive, then you are likely to have RA.

Interpreting CCP Test Results

The amount of time it takes to receive your results can vary. You may have to wait a couple of days or a week. Check with your healthcare provider if you are concerned about the waiting period. Your practitioner should receive the results and communicate with you.

Reference Ranges: What Is Low, Normal, and High?

When you receive the test results, you will see numbers in a reference range. They may be reported in either U/mL (units per milliliter) or U (units).

Reference ranges for test results (may vary depending on the precise test used):

Negative: <7 U/mL or <20 U
Weak positive: 7-10 U/mL or 20-39 U
Positive: >10 U/mL or 40-59 U
Strong positive: > or = 60 U

The < means less than, > means greater than, and the = means equal.

A negative CCP antibody blood test means you do not have detectable antibodies, but you may still have rheumatoid arthritis. It is possible for a person to have a negative test result and have RA at the same time.

A positive CCP antibody test means you have these antibodies in your blood and may have RA. A strong positive test result means you have more of the CCP antibodies in your blood, so you are even more likely to have RA.

If you have a weak positive test, your healthcare provider may recommend repeating the test in the future.

It is rare for someone to have cyclic citrullinated peptide antibodies in their blood without also having RA. However, other autoimmune conditions can also test positive for CCP antibodies.

Autoimmune conditions that may show positive test results for CCP antibodies include:

Type 1 autoimmune hepatitis (chronic liver disease)
Psoriatic arthritis
Palindromic rheumatism
Systemic sclerosis
Sjögren's syndrome
Systemic lupus erythematosus
Seronegative arthritis
Osteoarthritis

What Is a Normal Cyclic Citrullinated Peptide?

A normal level of CCP, or negative test, is one with results of less than 20 units per milliliter.

Follow-Up

If you have a weak positive blood test, your healthcare provider may recommend testing again in a couple of weeks or months to see if the results change. Your practitioner may also order CCP antibody tests periodically to see if your RA treatments are working.

Since there is not a single test for diagnosing RA, your healthcare provider may order other imaging and blood tests in addition to the CCP antibody test. Talk to your practitioner to see which tests are best for you.

If you are diagnosed with RA, your healthcare provider will help you figure out the next steps. You may need to make some lifestyle changes, such as improving your diet, getting enough exercise, and reducing stress. You may also have to take medications for RA.

Other Considerations

You should follow up with your healthcare provider to talk about the results of your CCP antibody test. It is important to have an open dialogue, so you can ask questions and understand what the blood test results mean. You should also discuss the next steps like additional testing or medications.

If you would like to retake the CCP antibody test, talk about it with your healthcare provider. In some circumstances, such as a weak positive result, it makes sense to retake the blood test.

A Word From Verywell

Having a blood test and waiting for the results can be stressful. Reach out to your healthcare provider, family, and friends during this time for support. Talk about your feelings and concerns with them. In addition to the CCP antibody test, you may have other blood and imaging tests. Focus on staying organized and maintaining the highest possible quality of life.

10 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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Arthritis Foundation. Rheumatoid arthritis.
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Iwasaki T, Nakabo S, Terao C, et al. Long-term follow-up of patients with anti-cyclic citrullinated peptide antibody-positive connective tissue disease: a retrospective observational study including information on the HLA-DRB1 allele and citrullination dependency. Arthritis Res Ther. 2020;22(1):248. doi:10.1186/s13075-020-02351-4
Vannini A, Cheung K, Fusconi M, et al. Anti-cyclic citrullinated peptide positivity in non-rheumatoid arthritis disease samples: citrulline-dependent or not?. Ann Rheum Dis. 2007;66(4):511-516. doi:10.1136/ard.2006.058933
Hospital for Special Surgery. Understanding Rheumatoid Arthritis.

By Lana Bandoim
Lana Bandoim is a science writer and editor with more than a decade of experience covering complex health topics.

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