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)

How is it used?

The AMA test is ordered to help diagnose primary biliary cirrhosis (PBC). PBC is a serious condition in which the biliary system in the liver is gradually destroyed. (For more about this disease, see the links listed under Elsewhere on the Web).

Other tests that may be ordered include:

These tests often help detect PBC, distinguishing it from other autoimmune conditions causing liver damage, and may be useful predictors of need for a liver transplant.

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When is it ordered?

The AMA or AMA-M2 test is ordered when your doctor suspects that you have an autoimmune disorder such as PBC. You may have symptoms such as an enlarged liver and spleen, fatigue, jaundice, and itchiness, but many patients affected with early PBC do not have any symptoms. The condition is often initially identified because a patient has elevated liver enzymes, especially alkaline phosphatase (ALP), that are found during routine blood tests.

An AMA or AMA-M2 test may be ordered along with or following a variety of tests that are used to help diagnose and/or rule out other causes of liver disease or injury. These causes can include infections, such as viral hepatitis, drugs, alcohol abuse, toxins, genetic conditions, metabolic conditions, and autoimmune hepatitis.

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What does the test result mean?

When significant amounts of AMA or AMA-M2 are present in the blood, the most likely cause is PBC. Low levels of AMA may also be present in patients with chronic active hepatitis, autoimmune hepatitis, liver or bile obstruction, and with infections such as syphilis or acute infectious hepatitis. It may also be present in patients with other autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, scleroderma, and .

Levels of AMA may be lower in children and in those with compromised immune systems. The level of AMA is not related to the severity of PBC symptoms or to a patient’s prognosis.

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Is there anything else I should know?

By themselves, AMA and AMA-M2 are not diagnostic of PBC, but in conjunction with other laboratory tests and clinical symptoms, the diagnosis of PBC can be made. When significant levels of AMA or AMA-M2 are present and the doctor suspects PBC, a liver biopsy may be performed to look for characteristic signs of primary biliary cirrhosis in the liver tissue. Imaging scans of the liver may also be ordered to look for bile duct obstructions.

About 50% of the cases of PBC will be discovered before the patient has noticeable symptoms.

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