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Related to rheumatoid factors: RF test
rheu·ma·toid fac·tors (RF),
antibodies in the serum of patients with rheumatoid arthritis. These factors are autoantibodies of the classes IgM, IgG, and IgA. The most common factor is IgM and is the one usually measured. Rheumatoid factors also occur in other autoimmune and certain infectious diseases.
rheu·ma·toid fac·tors(rū'mă-toyd fak'tŏrz)
Antibodies in the serum of people with rheumatoid arthritis that react with antigenic determinants or immunoglobulins that enhance agglutination of suspended particles coated with pooled human gamma-globulin; also occur in other autoimmune diseases and certain infectious diseases.