Confirmatory Lupus (Sm) Test - Anti-Smith (Sm) Antibody Test

A serological test to detect autoantibodies directed against Smith protein (Sm) antigens, which are small RNA-linked nuclear proteins (snRNPs). These antibodies are highly specific for systemic lupus erythematosus (SLE), with a specificity of >99%. They are present in approximately 10–30% of SLE patients and are often associated with more active disease involving multiple organ systems, including the central nervous system and kidneys.