Anti-Smooth Muscle Antibody Test

Test Description

The anti-smooth muscle antibody (ASMA) test is used to detect the presence of
autoimmune antibodies that have formed against smooth muscle. These antibodies
have a tendency to appear in chronic active hepatitis and other diseases in which
there is liver damage. The ASMA test is used in the diagnosis of primary biliary cirrhosis
and chronic active hepatitis

Normal Values

Negative at 1:20 dilution

Possible Meanings of Abnormal Values
Increased
Acute viral hepatitis
Chronic active hepatitis
Infectious mononucleosis
Intrinsic asthma
Malignancies
Primary biliary cirrhosis
Viral infection

Contributing Factors to Abnormal Values

• Hemolysis of the blood sample and the presence of antinuclear antibodies may alter
test results.

Interventions/Implications

Pretest
• Explain to the patient the purpose of the test and the need for a blood sample to be
drawn.
• No fasting is required before the test.

Procedure

• A 7-mL blood sample is drawn in a red-top collection tube.
• Gloves are worn throughout the procedure.

Post test

• Apply pressure at venipuncture site. Apply dressing, periodically assessing for continued
bleeding.
• Label the specimen and transport it to the laboratory.
• Report abnormal findings to the primary care provider.

Clinical laboratory        
• Prolonged bleeding from the venipuncture site due to vitamin K deficiency may
occur secondary to liver dysfunction, as seen in severe hepatitis.
• The ASMA test is usually performed in conjunction with the antimitochondrial
antibody (AMA) test.
•Interpretation of this test involves noting whether it is positive or negative; the
level of titer does not correspond to severity of disease or response to treatment.