Also Known As
Centromere Antibody
ACA
This article was last reviewed on
This article waslast modified on November 13, 2019.
At a Glance
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

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Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

For more information, please read the article Reference Ranges and What They Mean.

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.

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

No test preparation is needed.

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Common Questions
  • 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.

  • 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.

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

    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 someone has developed ACA, that person will continue to produce them for life.

  • 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.

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Related Content

On This Site

Tests: ANA, Autoantibodies, ENA Panel

Conditions: Scleroderma, Autoimmune Disorders

Elsewhere On The Web

American Academy of Family Physicians: Scleroderma  
MedlinePlus Medical Encyclopedia: Scleroderma  
National Institute of Arthritis and Musculoskeletal and Skin Disease: Handout on Health - Scleroderma  
Womenshealth.gov: Autoimmune diseases fact sheet  
Scleroderma Research Foundation

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View Sources

Sources Used in Current Review

Reviewed January 2016 by Boris Calderon, MD, DABCC, FACB, NIH.

Tamby MC, Chanseaud Y, Guillevin L, Mouthon L. New insights into the pathogenesis of systemic sclerosis. Autoimmunity Reviews. 2003;2(3):152-7. PubMed PMID: 12848956.

Gabrielli A, Avvedimento EV, Krieg T. Scleroderma. New England Journal of Medicine. 2009;360(19):1989-2003. doi: 10.1056/NEJMra0806188. PubMed PMID: 19420368.

White, B. Systemic sclerosis. In Clinical Immunology Principles and Practice. Second edition. Edited by R Rich, T Fleisher, W Shearer, et al. St. Louis, Mosby-Year Book, 2001, Chapter 64, pp 64.1-64.10.

(January 25, 2016). Varga, J. Diagnosis and differential diagnosis of systemic sclerosis (scleroderma) in adults. In: UpToDate., Axford, JS (Ed). UpToDate, Waltham, MA. Available online at http://www.uptodate.com/contents/diagnosis-and-differential-diagnosis-of-systemic-sclerosis-scleroderma-in-adults. Accessed on January 25, 2016.

Sources Used in Previous Reviews

Yoon, J. and Raugi, G. (2012 January 13). CREST Syndrome. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1064663-overview. Accessed February 2012.

(© 1995-2012). Test ID: CENTA Centromere Antibodies, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/110006. Accessed February 2012.

Hill, H. and Tebo, A. (Updated 2011 May). Scleroderma - Systemic Sclerosis. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/SystemicSclerosis.html. Accessed February 2012.

(Updated 2010 May). Handout on Health: Scleroderma. National Institute of Arthritis and Musculoskeletal and Skin Diseases [On-line information]. Available online at http://www.niams.nih.gov/Health_Info/Scleroderma/default.asp. Accessed February 2012.

(©2012). Scleroderma, How is it Diagnosed? Arthritis Foundation [On-line information]. Available online at http://www.arthritis.org/disease-center.php?disease_id=26&df=diagnosed. Accessed February 2012.

Granito, A. (2012 January 31). Antinuclear Antibodies as Ancillary Markers in Primary Biliary Cirrhosis. Medscape News Today from Expert Rev Mol Diagn 12(1):65-74. [On-line information]. Available online at http://www.medscape.com/viewarticle/755110. Accessed February 2012.

Bellando-Randone, S. et. al. (2010 December 9). Patient Subgroups and Potential Risk Factors in Systemic Sclerosis: Is There a Possibility of an Early Diagnosis? Medscape Today from Int. J. Clin. Rheumatol 5(5):555-564. [On-line information]. Available online at http://www.medscape.com/viewarticle/731883. Accessed February 2012.

Assassi, S. et. al. (2009 October). Primary Biliary Cirrhosis (PBC), PBC Autoantibodies, and Hepatic Parameter Abnormalities in a Large Population of Systemic Sclerosis Patients. J Rheumatol. v36(10): 2250–2256. [On-line information]. PDF available for download at http://ukpmc.ac.uk/articles/PMC2885441/pdf/nihms201893.pdf. Accessed February 2012.

Magrey, M. and Abelson, A. (© 2000-2011). Laboratory Evaluation of Rheumatic Diseases. Cleveland Clinic [On-line information]. Available online at http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/rheumatology/laboratory-evaluation-rheumatic-diseases/. Accessed February 2012.

Makover, M. (Updated 2011 February 14). Scleroderma. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000429.htm. Accessed February 2012.

Hajj-ali, R. (Updated 2008 February). Systemic Sclerosis. Merck Manual for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed February 2012.

Li, S. (Updated 2012 January 30). Pediatric Raynaud Phenomenon. Medscape Reference from [On-line information]. Available online http://emedicine.medscape.com/article/1355650-overview. Accessed February 2012.

Harris, M. and Rosen, A. (2003 November 18). Autoimmunity on Scleroderma: The Origin, Pathogenic Role, and Clinical Significance of Autoantibodies. Medscape Today from Curr Opin Rheumatol 15(6). [On-line information]. Available online http://www.medscape.com/viewarticle/463925. Accessed February 2012.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 73.

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