To detect the presence of anticentromere antibodies; to help diagnose limited cutaneous scleroderma, a subtype of scleroderma
Anticentromere Antibody
When you have one or more symptoms that suggest CREST syndrome; when you have a positive result on an antinuclear antibody (ANA) test
A blood sample drawn from a vein in your arm
None
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How is the test 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.
An ACA test may be ordered along with other tests for autoantibodies, including ANA (antinuclear antibody) testing. ACA testing may be used to provide your healthcare practitioner with additional information if an ANA test is positive, especially if the test produces a certain pattern characteristic of particular antibodies. (For more on this, see the "What does the test result mean?" section in the ANA article.)
An ACA test may be ordered along with a Scl-70 (anti-topoisomerase I) test. Scl-70 is another autoantibody that may be present with scleroderma. An anti-RNA polymerase III autoantibody (ARA) test may also be ordered in the diagnosis of systemic sclerosis. These autoimmune antibody tests could be performed as part of an Extractable Nuclear Antigen (ENA) antibody panel, or other antibody panels for autoimmune disorders and/or systemic sclerosis.
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When is it ordered?
The ACA test may be ordered when you have a positive result on an ANA test and/or 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
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What does the test result mean?
If a your ACA result is positive, indicating you have anti-centromere antibodies in your blood, and you have symptoms of CREST, then it is likely that you have 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. Around 5-7% of ACA positive patients develop diffuse cutaneous scleroderma.
If your ACA result is negative, then it is likely that your symptoms are due to another condition. However, it is possible, though rare, that you have limited cutaneous scleroderma and do not produce anticentromere antibodies, resulting in a negative ACA test.
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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 such as ANA testing.
The amount of ACA present does not, in general, correlate to the severity of signs and symptoms.
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What other lab tests may be done?
In addition to ACA testing, other laboratory tests may be ordered to monitor your health status, including:
- Complete blood count (CBC) – to evaluate red and white blood cells
- Comprehensive metabolic panel (CMP) – to evaluate organ function and chemical and electrolyte balances
- Urinalysis
- Thyroid function tests
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Is there anything I can do to decrease my anticentromere antibody level?
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Will my anticentromere antibody ever go away?
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Can anticentromere testing be done at my healthcare practitioner's office?
No. ACA testing requires collection of a blood sample by a trained medical professional. The testing itself requires specialized equipment and trained medical laboratory personnel. It is not offered by every laboratory and usually is performed by a reference laboratory.