Print By Mayo Clinic Staff Request an appointment About May 16, 2026 PrintShow references Firestein GS, et al. Autoantibodies in rheumatoid arthritis. In: Firestein & Kelley's Textbook of Rheumatology. 12th ed. Elsevier; 2025. https://www.clinicalkey.com. Accessed April 4, 2025. Rheumatoid factor (RF) test. Testing.com. https://www.testing.com/tests/rheumatoid-factor-rf/. Accessed April 4, 2025. Shmerling RH, et al. Rheumatoid factor: Biology and utility of measurement. https://www.uptodate.com/contents/search. Accessed April 4, 2025. Ferri FF. Rheumatoid arthritis. In: Ferri's Clinical Advisor 2025. Elsevier; 2025. https://www.clinicalkey.com. Accessed April 4, 2025. Related Juvenile idiopathic arthritis Psoriatic arthritis Rheumatoid arthritis News from Mayo Clinic Rewriting the future of rheumatoid arthritis: How early detection is transforming prevention Products & Services A Book: Mayo Clinic Family Health Book A Book: Mayo Clinic Guide to Arthritis Newsletter: Mayo Clinic Health Letter — Digital Edition Show more products and services from Mayo Clinic Rheumatoid factorAbout PRC-20198136 Tests & Procedures Rheumatoid factor