Anticentromere Antibody

Also Known As

Centromere Antibody

ACA

This article was last reviewed on

30 September 2024.

This article waslast modified on 9 December 2024.

At a Glance

Why Get Tested?

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

When To Get Tested?

When you have one or more symptoms that suggest limited cutaneous systemic sclerosis, also known as CREST syndrome

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

No test preparation is needed

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

The anticentromere antibody (ACA) is an antibody (a protein produced by the immune system) that targets the body's own tissues. ACA targets the centromere, part of the chromosomes found in the nucleus of the body's cells. The ACA is one of several autoantibodies that can be seen in the anti-nuclear antibody test. We detect ACA in the serum separated from blood.

The ACA test is used to help diagnose systemic sclerosis and scleroderma. Scleroderma is actually a spectrum of rare “connective tissue” disorders that range from localised forms affecting only the skin (limited cutaneous systemic sclerosis) to diffuse forms that affect the skin and internal organs (diffuse systemic sclerosis). ACA is most associated with the limited cutaneous form (seen in about 60-80% of people). Only a small number of patients (approximately 5%) with diffuse disease will show positive antibodies to ACA. Limited cutaneous systemic sclerosis is often 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

Common Questions

How is it used?

An anticentromere antibody (ACA) test is primarily requested to help diagnose limited cutaneous systemic sclerosis. The test may be used to distinguish between this and other conditions with similar symptoms.

Testing may be used to provide the doctor 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 "What does the test result mean?" in the ANA article.)

It may be requested along with Scl-70 (anti-topoisomerase), another autoantibody that may be present in patients with systemic sclerosis. An ACA test may be requested along with other tests for autoantibodies, including ANA.
When is it requested?
An ACA test may be requested 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 systemic sclerosis. ACA is found in about 60-80% of people who have limited cutaneous systemic sclerosis and can be present in up to 95% of those who have CREST syndrome.

If a person is negative for ACA, then it is likely that their symptoms are due to another condition. However, it is possible, though rare, that the individual has limited cutaneous systemic sclerosis and does not produce anticentromere antibodies.
Is there anything else I should know?

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

The amount of ACA present does not, in general, correlate to the severity of a person's symptoms.
Should everyone have an anticentromere test?

This test is not a general screening test. It is typically indicated when a person has symptoms that could be associated with scleroderma or CREST syndrome. Scleroderma and limited cutaneous scleroderma are relatively rare conditions so most people will never need to have this test performed.
Is there anything I can do to decrease my anticentromere antibody level?

In general, no, it does not respond to lifestyle changes.
Will my anticentromere antibody ever go away?

Concentrations of ACA in the blood may vary over time but once a person has developed ACA, they will continue to produce it.
Can I perform anticentromere testing at home?

No. ACA testing requires specialised equipment and training. It is not offered by every laboratory and will usually need to be sent to a reference laboratory.

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