Rheumatoid Factor (RF)

Analyte [material]

Rheumatoid factor (RF) [P]

Reference range, target level, or decision threshold

Latex (IgM) <1/40

Immunonephelometry (IgM) <40 units/mL

Immunochemistry (IgG, IgA, IgE): depends on the reagents used

Interpretation of results

↑ Rheumatoid arthritis, systemic lupus erythematosus, systemic scleroderma, mixed connective tissue disease, Sjögren syndrome, polymyositis or dermatomyositis, cryoglobulinemia, chronic hepatitis, chronic inflammatory pulmonary conditions, malignancies, AIDS, infectious mononucleosis, influenza, tuberculosis, leprosy, syphilis, brucellosis, salmonellosis, subacute endocarditis, healthy individuals