Sm Antibody Smith Antibody Serum

The Sm Antibody Smith Antibody Serum test detects the presence of antibodies against the Smith antigen, a protein found in the nucleus of cells. These antibodies are most commonly associated with systemic lupus erythematosus (SLE), an autoimmune disease where the immune system attacks healthy tissues. A positive result for Sm antibodies is highly specific for SLE and can help confirm the diagnosis, especially when combined with other clinical findings. A negative result does not rule out lupus entirely, as some people with SLE may not have these antibodies. Additional tests may be needed to confirm a diagnosis or explore other possible autoimmune conditions.