Patient Test Information

Anticentromere Antibody

Also known as:

Centromere Antibody; ACA

Formal name:

Anticentromere Antibody

Related tests:

ANA, Autoantibodies, ENA Panel

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Why Get Tested?

To detect the presence of anticentromere antibodies; to help diagnose limited cutaneous scleroderma

When to Get Tested?

When you have one or more symptoms that suggest CREST syndrome

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

How is it used?

The anticentromere antibody (ACA) test is primarily ordered to help diagnose the autoimmune disorder limited cutaneous scleroderma, a form of systemic scleroderma, and CREST syndrome. The test may be used to distinguish between this and other conditions with similar symptoms.

ACA is an autoantibody, a protein produced by the immune system that mistakenly targets the body's own tissues. (For more on this, see the "What is being tested?" section and the article on scleroderma.)

ACA testing may be used to provide a healthcare practitioner with additional information if an ANA (antinuclear antibody) test is positive, especially if the test produces a speckled, nucleolar, or centromere pattern. (For more on this, see the "What does the test result mean?" section in the ANA article.)

It may be ordered along with a Scl-70 (anti-topoisomerase) test, usually performed as part of an ENA panel (Extractable Nuclear Antigen antibody panel). Scl-70 is another autoantibody that may be present with scleroderma.

An ACA test may be ordered along with other tests for autoantibodies, including ANA.

When is it ordered?

The ACA test may be ordered when a person has a positive result on an ANA test and one or more of the symptoms associated with CREST. These symptoms include:

  • Calcinosis - calcium deposits under the skin
  • Raynaud phenomenon - episodes of decreased blood flow to fingers and toes, causing them to turn white and blue
  • Esophageal dysfunction - difficulty swallowing, acid reflux, and heartburn
  • Sclerodactyly - tight, thick, shiny skin on the hands and fingers
  • Telangiectasia - red spots on skin due to swollen capillaries

What does the test result mean?

If a person is positive for ACA and has symptoms of CREST, then it is likely that the person has limited cutaneous scleroderma. ACA is found in about 60-80% of people who have limited cutaneous scleroderma and can be present in up to 95% of those who have CREST syndrome.

If someone is negative for ACA, then it is likely that the person's symptoms are due to another condition. However, it is possible, though rare, that the individual has limited cutaneous scleroderma and does not produce anticentromere antibodies.

Is there anything else I should know?

ACA can be positive in some other autoimmune disorders, such as lupus, rheumatoid arthritis, or primary biliary cirrhosis.

Typically, only people who have CREST symptoms are tested for ACA. However, some people may be positive for ACA prior to the development of these symptoms and ACA may be performed in conjunction with testing for other autoimmune disorders.

The amount of ACA present does not, in general, correlate to the severity of a person's symptoms.

What is being tested?

The anticentromere antibody (ACA) is an autoantibody, a protein produced by the immune system that mistakenly targets the body's own tissues. ACA is one of several antinuclear antibodies and targets the centromere, a component of the chromosomes (structures in the nucleus) found in all nucleated cells in our body except red blood cells. The ACA test detects and measures the amount of anticentromere antibody found in blood to help diagnose a form of scleroderma.

Scleroderma (also known as systemic sclerosis) is a group of rare connective tissue disorders. There are two distinct subtypes: diffuse cutaneous systemic sclerosis that affects the entire body and limited cutaneous systemic sclerosis. These subsets of systemic sclerosis are defined on the basis of the extent of skin involvement. ACA is found in about 60-80% of people who have limited cutaneous scleroderma; only about 5% of patients with diffuse scleroderma have ACA.

Limited cutaneous scleroderma is typically associated with one or more symptoms that are known collectively as CREST syndrome.

CREST syndrome symptoms include:

  • Calcinosis - calcium deposits under the skin
  • Raynaud phenomenon - episodes of decreased blood flow to fingers and toes, causing them to turn white and blue
  • Esophageal dysfunction - difficulty swallowing, acid reflux, and heartburn
  • Sclerodactyly - tight, thick, shiny skin on the hands and fingers
  • Telangiectasia - red spots on skin due to swollen capillaries

ACA can be present in up to 95% of people who have CREST syndrome.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

  1. Should everyone have an anticentromere test?

    This test is not intended to be a general screening test. It is typically only indicated when a person has symptoms associated with CREST. Since limited cutaneous scleroderma is relatively rare, most people will never need to have this test performed.

  2. Is there anything I can do to decrease my anticentromere antibody level?

    No, it does not respond to lifestyle changes.

  3. Will my anticentromere antibody ever go away?

    Concentrations of ACA in the blood may vary over time, but once someone has developed ACA, that person will continue to produce them for life.

  4. Can I perform anticentromere testing at home?

    No. ACA testing requires specialized equipment and training. It is not offered by every laboratory and usually is performed be a reference laboratory.