Rheumatoid Factor (RF Test)

The rheumatoid factor (RF) blood test measures the presence of an antibody often found in people with rheumatoid arthritis. It may also be elevated in other autoimmune or chronic inflammatory conditions. While not diagnostic on its own, it helps support clinical evaluation of joint pain and stiffness.

• No fasting is usually required.
• Inform your provider about medications or conditions that may affect test results.

A blood sample is drawn from a vein in your arm. The collection process takes only a few minutes.

• Minor pain, bruising, or bleeding at the blood draw site.
• Rare risk of infection.

Results are typically available within a few days. A positive RF test does not always mean rheumatoid arthritis, as levels can be elevated in other conditions. Your doctor will interpret the results alongside physical exam findings and other lab tests (such as anti-CCP antibody).