Description
verview: Anti-Smooth Muscle Antibodies (ASMA) are proteins produced by the immune system that target the smooth muscle fibers found in the liver and other organs. This test uses Immunofluorescence Assay (IFA) to detect these antibodies. When the test is done “in dilutions,” the blood is diluted in steps (e.g., 1:20, 1:40, 1:80) to determine the highest dilution at which antibodies are still detectable. This provides a “titer” result.
Clinical Significance:
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Autoimmune Hepatitis (AIH): High titers of ASMA (typically >1:80) are the hallmark of Autoimmune Hepatitis Type 1, a chronic disease where the body attacks its own liver.
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Differentiating Liver Disease: Low titers (e.g., 1:20 or 1:40) can sometimes be seen in viral hepatitis (Hepatitis B or C) or fatty liver disease. High titers strongly point toward an autoimmune cause, helping doctors decide if immunosuppressive treatment is needed.
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Primary Biliary Cholangitis (PBC): ASMA can occasionally be present in PBC, though other markers (like AMA) are more specific for that condition.
When is this test recommended?
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To investigate abnormal liver function tests (high AST/ALT) when the cause is unknown.
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When a patient has symptoms of liver damage (jaundice, fatigue, abdominal pain) and viral hepatitis has been ruled out.
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To monitor the response to treatment for Autoimmune Hepatitis (titers may decrease as the liver heals).
Sample Requirements:
- Specimen: Serum (Blood).
- Container: Gold Top (SST) or Red Top Tube.
- Preparation: No special preparation or fasting is typically required.
