anti-smooth muscle antibody

Anti-smooth muscle antibody (SMA) is an autoantibody that uses the body's smooth muscle tissue as an antigen. It has no organ and species specificity, mainly IgG and IgM types. Tissues such as rat liver, kidney, human thyroid and platelets share common antigenicity with actomyosin of smooth muscle. Therefore, using purified myosin as an antigen, SMA can be detected by precipitation test, indirect hemagglutination test, radioimmunoassay and enzyme immunoassay. However, the most commonly used indirect immunofluorescence method is to use smooth muscle as an antigenic sheet. Basic Information Specialist classification: growth and development check classification: immunological examination Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: normal. Positive: Prompt for autoimmune diseases. Tips: Individual normal elderly can sometimes be positive. Normal value Serum SMA was negative in the normal population, titer <1:10 (indirect immunofluorescence). The positive rate of SMA in the elderly population is about 5%. Clinical significance (1) SMA is mainly found in autoimmune (lupus-like) hepatitis, which can be used to identify with SLE. In primary biliary cirrhosis and chronic active hepatitis, the positive rate of this antibody is higher, but the latter serum SMA titer is very high. Low, acute viral hepatitis SMA positive rate can be as high as 80%, mostly in the first week of onset. (2) SMA is also found in other diseases, such as mycoplasmal pneumonia, infectious mononucleosis, leprosy, children with skin mucosal lymph node syndrome, syphilis, Sjogren's syndrome, rheumatoid arthritis, etc., tumor and viral infections. There are also different levels of positive detection rates. Precautions Individual normal elderly can sometimes be positive. Inspection process Same as indirect fluorescence method. Not suitable for the crowd There are no taboos. Adverse reactions and risks There are no related complications and hazards.