Medical Definition of Rheumatoid factor
Rheumatoid factor: An antibody that is measurable in the blood and is used to diagnose rheumatoid arthritis. Rheumatoid factor is present in about 80 percent of adults, and a much lower proportion of children, who have rheumatoid arthritis. It is also present in patients with other connective-tissue diseases, such as systemic lupus erythematosus, and in some patients with infectious diseases, such as infectious hepatitis.
Quick GuideRheumatoid Arthritis (RA) Symptoms & Treatment
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