Factor, rheumatoid: See rheumatoid factor.
This test detects and measures rheumatoid factor (RF) in the blood. RF is an autoantibody, an IgM (immunoglobulin M) protein that is produced by the body's immune system.
About 80% of patients with rheumatoid arthritis test positive for rheumatoid factor. The other 20% have seronegative rheumatoid arthritis.
Read about the rheumatoid factor (RF) blood test used for the diagnosis of rheumatoid arthritis, lupus and sarcoidosis. Elevated results, or high levels, indicate severe ...
Rheumatoid factor â€” Overview covers definition, risks, results of rheumatoid factor blood test.
WebMD explains the rheumatoid factor test for RA, including how it's done, how to prepare, and what the results mean.