The AMA test or the AMA-M2 test may be 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 on the Related Pages tab under Elsewhere on the Web).
Many of those affected with early PBC do not have any symptoms. The condition is often initially identified because a person has abnormal results on a liver panel (elevated liver enzymes), especially alkaline phosphatase (ALP).
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.
A high AMA or AMA-M2 level (titer) in the blood indicates that the most likely cause of symptoms and/or liver damage is PBC. The level of AMA is not related to the severity of PBC symptoms or to a person's prognosis.
A negative AMA or AMA-M2 means that it is likely that a person's symptoms are due to something other than PBC, but the result does not rule out the condition. About 5-10% of those with PBC will not have significant amounts of AMA or AMA-M2.
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. A liver biopsy may be performed to look for characteristic signs of primary biliary cirrhosis in the liver tissue and to confirm the diagnosis but is not always necessary. 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 a person has noticeable symptoms.
This article was last reviewed on May 8, 2013. | This article was last modified on December 17, 2013.
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