RF (Rheumatoid Factor)

What does this test measure?

Rheumatoid factors (RF), a group of mainly IgM autoantibodies directed against the Fc fragment of IgG molecules.

Why is it ordered?

RF is mainly present in rheumatoid arthritis but may also appear in chronic inflammatory and infectious diseases (endocarditis, malaria, syphilis, tuberculosis) and autoimmune diseases such as systemic lupus erythematosus.

Normal range

Adults: up to 30 IU/mL

Per the original BioSystems insert

Sample type

Serum