Anticentromere Antibody
Note: this site is for informational purposes only. To view test results or book a test, use the NHS app in England or contact your GP.
The anticentromere antibody test is a blood test in which a sample is drawn from a vein to detect antibodies targeting centromere proteins. It is used to help diagnose and support classification of autoimmune connective tissue disorders, particularly limited cutaneous systemic sclerosis (scleroderma).
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
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
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.
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
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.
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.
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.
In general, no, it does not respond to lifestyle changes.
Concentrations of ACA in the blood may vary over time but once a person has developed ACA, they will continue to produce it.
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.