Antimitochondrial antibodies (AMA) are substances (antibodies) that form against mitochondria. The mitochondria are an important part of cells. They are the energy source inside the cells and help the cells work properly.
This article discusses the blood test used to measure the amount of AMA in the blood.
How the Test is Performed
A blood sample is needed. It is most often taken from a vein. The procedure is called a venipuncture.
How to Prepare for the Test
Your health care provider may tell you not to eat or drink anything for up to 6 hours before the test (most often overnight).
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
You may need this test if you have signs of liver damage. This test is most often used to diagnose primary biliary cirrhosis (PBC).
The test may also be used to tell the difference between bile system-related cirrhosis and liver problems due to other causes such as a blockage, viral hepatitis, or alcoholic cirrhosis.
Normally, there are no antibodies present.
What Abnormal Results Mean
This test is important for diagnosing PBC. Almost all people with the condition will test positive. It is rare that a person without the condition will have a positive result.
Abnormal results may also be found, less often, in people with other kinds of liver disease and some autoimmune diseases.
Risks for having blood drawn are slight but can include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Angulo P, Lindor KD. Primary biliary cirrhosis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 89.
Muratori L, Granito A, Muratori P, et al. Antimitochondrial antibodies and other antibodies in primary biliary cirrhosis: diagnostic and prognostic value. Clin Liver Dis. 2008;12:261. PMID: 18456179 www.ncbi.nlm.nih.gov/pubmed/18456179.
Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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