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. These 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. Others may 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 cholangitis, formerly called primary biliary cirrhosis (PBC).
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.
Rarely, abnormal results may also be found. This may occur due to 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)
Beuers U, Gershwin ME, Gish RG, et al. Changing nomenclature for PBC: From 'cirrhosis' to 'cholangitis'. Clin Res Hepatol Gastroenterol. 2015;39(5):e57-e59. PMID: 26433440 www.ncbi.nlm.nih.gov/pubmed/26433440.
Chernecky CC, Berger BJ. A. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:84-180.
Eaton JE, Lindor KD. Primary biliary cirrhosis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 91.
Zhang J, Zhang W, Leung PS, et al. Ongoing activation of autoantigen-specific B cells in primary biliary cirrhosis. Hepatology. 2014;60(5):1708-1716. PMID: 25043065 www.ncbi.nlm.nih.gov/pubmed/25043065.
Review Date 2/8/2017
Updated by: 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, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.