Clinical Information

Rheumatoid factors are a heterogeneous group of autoantibodies directed against the antigenic determinants on the Fc‑region of IgG molecules. They are important in the diagnosis of rheumatoid arthritis but can also be found in other inflammatory rheumatic diseases and in various non‑rheumatic diseases. They are also found in clinically healthy people over 60 years of age. Despite these restrictions, the detection of rheumatoid factors is a diagnostic criterion of the American College of Rheumatology for classifying rheumatoid arthritis.

These autoantibodies occur in all immunoglobulin classes (IgA, IgG, and IgM). This assay measures all three types of autoantibodies for a total rheumatoid factor result.