What is being tested?This test measures the amount of anti-smooth muscle antibodies (ASMA) in the blood. ASMA are proteins produced by the body’s immune system to work against its own cytoskeletal proteins. The production of ASMA is strongly associated with chronic autoimmune
hepatitis but may also be seen in other forms of
liver disease and with other
autoimmune disorders such as primary biliary cirrhosis. Autoimmune hepatitis presents as an acute or chronic inflammation of the liver that is not caused by another discernable cause (such as a viral infection, drug, toxin, hereditary disorder, or alcohol abuse). It can lead to
cirrhosis (liver damage and scarring) and, in some cases, to liver failure.
Autoimmune hepatitis can be found in anyone at any age, but about 80% of those affected are women. In the United States, more than 80% of patients with this disorder will have ASMA, either alone or along with ANA (antinuclear antibodies). Anti-actin is an antibody targeted at actin, a specific cytoskeletal protein. Some recent studies suggest that it is a more specific test than ASMA for diagnosing autoimmune liver disease, with about 52% to 85% of those affected having the anti-actin antibody.
