AMA

Also known as: Mitochondrial Antibody

Formal name: Antimitochondrial Antibody and Antimitochondrial M2 Antibody

Related tests: Antineutrophil cytoplasmic antibody (ANCA), Liver/Kidney microsomal antibody, Alkaline phosphatase (ALP), Alanine aminotransferase (ALT), Liver panel, Smooth muscle antibody (SMA), Antinuclear antibody (ANA)

The Test Sample

What is being tested?

This test measures the amount of antimitochondrial antibodies (AMA) present in the blood. The increased production of AMA is strongly associated with primary biliary cirrhosis (PBC). PBC is an autoimmune disorder that causes inflammation and scarring of the bile ducts inside the liver, causing progressive hepatic destruction and blockage of the bile flow. It is found most frequently in women between the ages of 35 and 60. More than 90% of those affected by PBC will have significant concentrations of antimitochondrial antibodies.

Increased AMA levels are also seen in primary and secondary sclerosing cholangitis, liver disease due to chronic inflammatory bowel disease, and bile duct obstruction. In addition, elevated serum alkaline phosphatase levels can also be present.

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 has been particularly evident in PBC, while the other antigen types may be found in other conditions. Some laboratories have started to offer the AMA-M2 instead of the AMA, which tests for all types together.

For more information on PBC and primary sclerosing cholangitis, click on the Links tab and see related 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.