Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services.


Print this article
Share this page:
Also known as: Mitochondrial Antibody
Formal name: Antimitochondrial Antibody and Antimitochondrial M2 Antibody

The Test Sample

What is being tested?

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

Primary biliary cirrhosis 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 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, click on the Related Pages tab and see links listed under Elsewhere on the Web.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

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

No test preparation is needed.