Rheumatoid factor is generally referred to as rheumatoid factor, which can be detected by means of latex agglutination test and ELISA. 1. Latex agglutination test: Rheumatoid factor is an autoantibody with denatured IgG as the target antigen. It is usually detected by latex agglutination test, in which denatured IgG is encapsulated in polystyrene latex particles, and the sensitized latex can be agglutinated when it encounters the rheumatoid factor in the serum to be tested, which is visible to the naked eye. This test can detect lgM rheumatoid factor in serum. 2. ELISA: ELISA is a solid-phase antibody formed by encapsulating denatured IgG. Serum to be tested is added to the microtiter wells of the reaction plate, and if rheumatoid factor is present, it will bind to it. Afterwards, enzyme-labeled heat-agglutinated denatured lgG is added, which results in a color development reaction. It can be used for the determination of different Ig classes of RF and is also quantitative. It is recommended that patients with positive rheumatoid factor and swollen joints seek medical attention for specific tests and treatments as prescribed by the doctor.