TABLE 1

Conditions associated with rheumatoid factor

ConditionFrequency
Rheumatoid arthritis70%
Other autoimmune rheumatic conditions
Primary Sjögren syndrome75%–95%
Systemic lupus erythematosus15%–35%
Systemic sclerosis20%–35%
Systemic vasculitis5%–20%
Infectionsa
Infective endocarditis40%
Syphilis8%–37%
Hepatitis B25%
Hepatitis C76%
Human immunodeficiency virus infection10%–20%
Tuberculosis15%
Other diseases
Liver cirrhosis25%
Mixed cryoglobulinemia100%
Primary biliary cirrhosis45%–70%
Healthy people5%–25%b

  • ↵a The rheumatoid factor in infectious diseases is produced by B cells, possibly to clear the immune complexes. They are usually transient and harmless.

  • ↵b The frequency rises with age (5% at age 50, rising to 10% to 25% at age 70.

  • Data from reference 3.