Rheumatoid factors (RF) is a collective name of a group of autoantibodies. They are directed against body-like IgG antibodies and have been described for the first time in high concentrations in patients with rheumatoid or rheumatic arthritis (RA). Even in healthy people, these rheumatic factors can be found in the blood. In general, values above 25 IU / ml are considered to be deviant. Patients with RA where these factors can not be demonstrated often have a milder disease than when they are present. The height of the mirrors is often related to the disease rate. Rheumatoid factor can be a cryoglobulin, and therefore precipitate in cold. That precipitation may cause additional symptoms (such as vessel wall inflammation). The physiological function of RF is likely to establish and remove immune complexes of antibodies. Due to this physiological function and the occurrence of RF in healthy people, testing for RF in the blood provides limited information: presence is not confirmation of having RA and absence does not exclude RA. Therefore, it is often necessary to take multiple tests before diagnosing RA. One of the tests that support this is to measure antibodies against cyclically citrinated peptide (anti-CCP antibodies). Also see
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