What is a rheumatoid factor (RF) test?
A rheumatoid factor (RF) test measures the amount of rheumatoid factor (RF) in your blood. Rheumatoid factors are proteins produced by the immune system. Normally, the immune system attacks disease-causing substances like viruses and bacteria. Rheumatoid factors attack healthy joints, glands, or other normal cells by mistake.
An RF test is most often used to help diagnose rheumatoid arthritis. Rheumatoid arthritis is a type of autoimmune disorder that causes pain, swelling, and stiffness of the joints. Rheumatoid factors may also be a sign of other autoimmune disorders, such as juvenile arthritis, certain infections, and some types of cancer.
Other names: RF Blood Test
