What Is the CCP Antibody Test?

The CCP (cyclic citrullinated peptide) antibody test measures CCP antibodies in the blood. CCP antibodies are proteins that are part of an immune system attack on healthy tissues and cells, such as the joints. A doctor 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, and anticitrullinated peptide antibody (ACPA).   

What Is Cyclic Citrullinated Peptide?

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 a lot of citrulline that 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.

Purpose of Test

The purpose of the CCP antibody test is to check if there are cyclic citrullinated peptide antibodies in the blood. A doctor 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.

A doctor may suspect you have RA based on your symptoms, such as fatigue, low-grade fever, joint pain, stiffness, and 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.

In addition to helping your doctor 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.

Another blood test a doctor 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 have or will develop RA. Your doctor may order other blood tests during the RA diagnosis process, including erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), antinuclear antibody (ANA), and a complete blood count (CBC). You may also have imaging tests to check your joints for damage, such as an X-ray, MRI, or ultrasound scan.

What Is Rheumatoid Arthritis?

Rheumatoid arthritis (RA) is an autoimmune condition that mostly affects the joints in your body. An autoimmune condition means that your immune system attacks healthy tissues and cells. RA can affect your joints, lungs, heart, and eyes. It causes inflammation or swelling in the joints, such as the hands, wrists, knees, and ankles.

Although symptoms can vary, early signs of RA are tenderness and pain in the joints. You may also experience stiffness, redness, and swelling in the joints. Other symptoms are fatigue and low-grade fever.

Research has not found what causes or triggers 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 and female.

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. One study found that it has an overall accuracy of 84.6%. The test’s sensitivity, or its ability to identify correctly those with RA, was 81.6%. The specificity, or ability to discern those without RA, was 87.5%. This blood test has a false negative rate of 18.4% and a false positive rate of 12.5%.

Rheumatoid Arthritis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Man

Before the Test

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

You should tell your doctor about any prescription medications, vitamins, dietary supplements, and over-the-counter drugs you are taking. Your doctor 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 doctor 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 doctor's office, laboratory, or hospital. Your doctor 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 doctor 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, then bring something to stay occupied with, 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. You may have a bandage put 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 doctor 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 doctor 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 the 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 doctor if you are concerned about the waiting period. Your doctor 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 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. A weak positive test is intermediate; your doctor 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:

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

Follow-Up 

If you have a weak positive blood test, your doctor may recommend testing again in a couple of weeks or months to see if the results change. Your doctor 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 doctor will order other imaging and blood tests in addition to the CCP antibody test. Talk to your doctor to see which tests you need. 

If you are diagnosed with RA, your doctor 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 have to take medications for RA.

Other Considerations 

You should follow up with your doctor 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 take the CCP antibody test again, talk about it with your doctor. In some circumstances, such as a weak positive result, it makes sense to have the blood test again. 

A Word From Verywell

Having a blood test and waiting for the results can be stressful and anxiety-provoking. It is important to reach out to your doctor, family, and friends during this time for support. Talk about your feelings and concerns with them. 

As you make your way through the entire diagnosis process for RA, it helps to have patience. In addition to the CCP antibody test, you may have other blood and imaging tests. Focus on staying organized and having the highest quality of life possible during the process. 

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Article Sources
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