Also Known As
Mitochondrial Antibody
Formal Name
Antimitochondrial Antibody and Antimitochondrial M2 Antibody
This article was last reviewed on
This article waslast modified on
February 1, 2018.
At a Glance
Why Get Tested?

To help diagnose primary biliary cholangitis, also sometimes called primary biliary cirrhosis (PBC)

When To Get Tested?

When you have abnormal results on a liver panel and/or symptoms that your healthcare practitioner suspects may be due to PBC

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

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?

Antimitochondrial antibodies (AMA) are autoantibodies that are strongly associated with primary biliary cholangitis (PBC), formerly called primary biliary cirrhosis. This test detects and measures the amount (titer) of AMA in the blood.

Primary biliary cholangitis is a chronic autoimmune disorder that causes inflammation and scarring of the bile ducts inside the liver. It is a slow-progressing disease that causes worsening liver destruction and blockage of the bile flow. Blocked bile ducts can lead to a build-up of harmful substances within the liver and may eventually lead to permanent scarring (cirrhosis). PBC is found most frequently in women between the ages of 35 and 60. About 90-95% of those affected by PBC will have significant titers of antimitochondrial antibodies.

AMA are autoantibodies that develop against antigens within the body. There are nine types of AMA antigens (M1 – M9) of which M2 and M9 are the most likely to cause illness (clinically significant). The presence of the M2 type of AMA has been particularly evident in PBC, while the other types may be found in other conditions. Some laboratories offer the AMA-M2 as a more specific test for PBC.

For more information on PBC, see the links in the Related Pages section.

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.

Accordion Title
Common Questions
View Sources

Sources Used in Current Review

Pyrsopoulos, N. and Reddy, K. (2016 June 3 Updated). Primary Biliary Cholangitis (Primary Biliary Cirrhosis). Medscape Drugs and Diseases. Available online at http://emedicine.medscape.com/article/171117-overview. Accessed on 02/18/17.

Lal, S. (2016 May 11 Updated). Primary biliary cirrhosis. MedlinePlus Medical Encyclopedia. Available online at https://medlineplus.gov/ency/article/000282.htm. Accessed on 02/18/17.

(2016 December 6, Updated). Primary Biliary Cholangitis (PBC, previously Primary Biliary Cirrhosis). American Liver Foundation. Available online at http://www.liverfoundation.org/abouttheliver/info/pbc/. Accessed on 02/18/17.

Tebo, A. (2016 November Updated). Primary Biliary Cirrhosis – PBC. ARUP Consult. Available online at https://arupconsult.com/content/primary-biliary-cirrhosis. Accessed on 02/18/17.

Shin, Y. (2014 December 5, Updated). Antimitochondrial Antibody. Medscape Laboratory Medicine. Available online at http://emedicine.medscape.com/article/2086548-overview Accessed on 02/18/17.

(2014 April Updated). Primary Biliary Cirrhosis. National Institute of Diabetes and Digestive and Kidney Diseases Available online at https://www.niddk.nih.gov/health-information/liver-disease/primary-biliary-cirrhosis. Accessed on 02/18/17.

(© 1995–2017). Mitochondrial Antibodies (M2), Serum. Mayo Clinic Mayo Medical Laboratories. Available online at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/8176. Accessed on 02/18/17.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO. Pp 82-83.

Lindor, K. (© 2002-2003) What is Primary Biliary Cirrhosis (PBC)? American Liver Foundation [On-line information]. Available online at http://www.liverfoundation.org/db/articles/1014.

(© 1995-2005). Primary Biliary Cirrhosis. The Merck Manual of Medical Information – Second Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/print/sec10/ch136/ch136d.html.

(© 1995-2005). Primary Sclerosing Cholangitis. The Merck Manual of Medical Information – Second Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/sec10/ch136/ch136e.html.

(© 2005). Mitochondrial M2 Antibody, IgG (ELISA). ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a89b.jsp#1142095.

Beuers, U. and Rust, C. (2005 October 27). Overlap Syndromes. Medscape, from Semin Liver Dis. 2005; 25(3): 311-320. [On-line information]. Available online at http://www.medscape.com/viewarticle/512463.

Stone, C. (2004 November 10, Updated). Autoimmune liver disease panel. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003328.htm.

Stone, C. (2004 May 14). Primary biliary cirrhosis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000282.htm.

Peng, S. (2005 April 20). Antimitochondrial antibody. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003529.htm.

(© 2003). Mitochondrial (M2) Antibody. LabCorp [On-line test information]. Available online at http://www.labcorp.com/datasets/labcorp/html/chapter/mono/se000750.htm.

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 85-86.

Clarke, W. and Dufour, D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 272.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition: Saunders Elsevier, St. Louis, MO. Pp 746.

Dugdale, D. (Updated 2008 November 2). Autoimmune liver disease panel. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003328.htm. Accessed 1/29/09.

Christopher-Stine, L. (Updated 2006 August 22). Systemic lupus erythematosus. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000435.htm. Accessed 1/29/09.

Lehrer, J (2006 July 25 Updated). Autoimmune hepatitis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000245.htm. Accessed 1/29/09.

Stone, C. (2008 May 20, Updated). Primary biliary cirrhosis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000282.htm. Accessed 1/29/09.

Hill, H. (Updated 2008 September). Primary Biliary Cirrhosis. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/AutoimmuneDz/PBC.html#. Accessed 1/29/09.

Bylund DJ, Nakamura RM. Organ-specific autoimmune diseases. Henry’s Clinical Diagnosis and Laboratory Management, 21st ed., 2007. Pp 945-960.

(Updated 2012 September 26). Antimitochondrial Antibody. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2086548-overview#showall. Accessed February 2013.

Tebo, A. (Updated 2012 August). Primary Biliary Cirrhosis – PBC. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/PBC.html?client_ID=LTD#tabs=0. Accessed February 2013.

(© 1995–2013). Mitochondrial Antibodies (M2), Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8176. Accessed February 2013.

Makover, M. (Updeate 2011 February 10). Antimitochondrial antibody. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003529.htm. Accessed February 2013.

Pyrsopoulos, N. and Reddy, K. (Updated 2012 January 4). Primary Biliary Cirrhosis. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/171117-overview. Accessed February 2013.

Dugdale, D. (Updated 2012 May 1). Primary biliary cirrhosis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000282.htm. Accessed February 2013.

Shaffer, E. (Reviewed 2009 June) Laboratory Tests of the Liver and Gallbladder. Merck Manual for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed February 2013.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 87-88.

McPherson, R. and Pincus, M. (© 2011). Henry's Clinical Diagnosis and Management by Laboratory Methods 22nd Edition: Elsevier Saunders, Philadelphia, PA. Pp 304.

Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL eds, (2005). Harrison's Principles of Internal Medicine, 16th Edition, McGraw Hill, Pp 1860-1861.

(April 30, 2012) National Digestive Diseases Information Clearinghouse. Primary Biliary Cirrhosis. Available online at http://digestive.niddk.nih.gov/ddiseases/pubs/primarybiliarycirrhosis/index.aspx. Accessed May 2013.

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