What is analysed?
Anti-smooth muscle antibodies (SMA) are antibodies that specifically target smooth muscle cells. The presence of SMA may suggest autoimmune hepatitis.
The SMA test is used as an initial screen to detect the presence of SMA in the blood and assess the need for additional tests.
What does the result mean?
The result indicates the presence or absence of SMA in the blood.
Why conduct the analysis?
The SMA test is conducted to help diagnose autoimmune hepatitis.
When to conduct the analysis?
The SMA test is conducted when symptoms of autoimmune hepatitis, such as jaundice, fatigue, or abdominal pain are observed.
What sample is required?
A blood sample is used for the analysis of SMA. The blood is drawn from a vein, usually in the arm.
Is any prior preparation necessary?
Patients should fast for 8-12 hours before the blood sample is taken. In addition, patients should also inform a healthcare professional about any medications being taken, as they could affect results.
How is it performed?
The collected blood sample is sent to a laboratory, where it is analysed using indirect immunofluorescence (IIF) or enzyme-linked immunosorbent assay (ELISA) for the presence of SMA in the blood.
What are the normal values?
Titres are used to measure SMA. A negative test result indicates that no SMA were detected.
Elevated titres of 1:40-1:640 are seen as a positive SMA test result.
What does having altered values mean?
- Positive result: A positive test result indicates the presence of SMA, which may suggest autoimmune hepatitis. However, a positive identification alone isn't a sure sign of an autoimmune disease. Further tests and a clinical evaluation are needed.