The SMA (or actin antibody), ANA, and rarely LKM1 tests are ordered when a healthcare practitioner suspects that someone has autoimmune hepatitis. They are usually ordered when a person presents with symptoms such as fatigue and jaundice along with abnormal findings on routine liver tests such as aspartate aminotransferase (AST) and/or bilirubin. These autoantibody tests may be ordered along with other testing when a healthcare practitioner is investigating liver disease and wants to distinguish between different causes of liver injury, including viral infections, drugs, alcohol abuse, toxins, genetic conditions, metabolic conditions, and autoimmune disorders. The ASMA test can also distinguish between autoimmune hepatitis and other causes of liver damage, such as systemic lupus erythematosus. ASMAs are present in people with autoimmune hepatitis. ASMAs are not found in people with lupus.
In this test the serum analysis of the smooth muscle antibody or actin antibody is done. A significant increase in the blood titer of SMA or actin antibody and/or ANA is usually due to autoimmune hepatitis type 1. A small increase in SMA or actin antibody may be present in up to 50% of patients with primary biliary cholangitis (PBC). The SMA autoantibody may also be found in other conditions, such as infectious mononucleosis, hepatitis C, and some cancers.
A negative SMA or actin antibody test and an increased titer of LKM1 may indicate autoimmune hepatitis type 2. Type 2 is uncommon in the United States.
If the SMA or actin antibody test and other antibody tests are negative, then symptoms and liver injury may be due to causes other than autoimmune hepatitis.
Blood tests are normally well-tolerated. Some people have smaller or larger veins, which may make taking a blood sample more difficult. However, risks associated with blood tests like the ACTH hormone test are rare. Uncommon risks of having blood drawn include: excessive bleeding lightheadedness or fainting hematoma, or blood pooling under the skin infection at the site
Early liver transplantation should be considered in such individuals. High-dose prednisone (60 mg/d) alone or prednisone (30 mg/d) plus azathioprine (150 mg/d) are alternative approaches when standard therapy fails. Patients whose condition is resistant to steroids can be treated with cyclosporine or tacrolimus.
Test Method 1 : To perform the ASMA test, a healthcare professional will get a blood sample from you. Usually, you give a blood sample in the following way:
The healthcare professional wraps an elastic band around your upper arm. This stops blood flow, makes your veins more visible, and makes it easier to insert the needle.
After they find your vein, the healthcare professional cleans your skin with alcohol and inserts a needle with a tube attached to collect the blood. As the needle goes in, you may feel a brief pinching or stinging sensation. You may also have some minor discomfort when the healthcare professional positions the needle in your vein.
After the professional collects enough of your blood, they’ll remove the elastic band from your arm. They remove the needle, and place gauze or a piece of cotton onto the site of the injection and apply pressure. They’ll secure the gauze or cotton with a bandage. And then the smooth muscle antibody analysis is done.
Report available : The turn around time for this test is around 24 hours.