What are antinuclear antibody tests (ANA)?
These detect a group of autoantibodies that are found in most people with lupus and scleroderma and in a few people with rheumatoid arthritis. These autoantibodies react with antigens in the nuclei of cells. The antibodies suggest that an autoimmune illness may be present, although many people test positive and have little evidence of serious disease. Specific antinuclear antibody tests are helpful in the diagnosis of certain rheumatic diseases that involve abnormalities in the immune system. The names of the following tests are abbreviations of more complicated-sounding tests. The diseases for which they are used include: • systemic lupus erythematosus (multiple-system illness, may involve the skin, joints, kidney, etc.); anti-dsDNA, anti-Sm, anti-Ro/SS-A, and antihistone tests help confirm the diagnosis. • scleroderma (a marked thickening of the skin); the anti-Scl-70 test helps confirm the diagnosis. • polymyositis (inflammation of muscles, resulting in muscle weakness, sometimes wi
