What Are the Normal Ranges for a Rheumatoid Factor Test?

Rheumatoid factor (RF) is an immune system protein that can target healthy cells in the body. The RF test, which is a blood test, plays a significant role in diagnosing rheumatoid arthritis. Although rheumatoid factor is closely associated with rheumatoid arthritis, its presence is not exclusive to this disease. In fact, when rheumatoid factor was first discovered, its primary application was in diagnosing rheumatoid arthritis. It’s noteworthy that about 80% of adult rheumatoid arthritis patients test positive for rheumatoid factor.

Rheumatoid factor is an autoantibody found in the blood. Unlike regular antibodies that protect the body from foreign invaders, autoantibodies can be harmful. In the context of RA, rheumatoid factor responds to inflammation caused by the disease. There are other blood tests used in tandem with the RF test to ascertain a diagnosis of rheumatoid arthritis. These tests might include Anti-nuclear antibody (ANA), Anti-cyclic citrullinated peptide (anti-CCP) antibodies, C-reactive protein (CRP), and Erythrocyte sedimentation rate (ESR or sed rate).

Contrary to its name, rheumatoid factors (RF) are not exclusive to rheumatoid arthritis (RA). They are present in a variety of pathologies, encompassing both autoimmune and non-autoimmune diseases. Surprisingly, RFs have been detected in up to 4% of young, healthy individuals and are also found in the elderly.

Rheumatoid arthritis itself is an autoimmune condition where the body’s immune system mistakenly attacks its own tissues. This includes joints and internal organs, leading to symptoms like pain and swelling. For a deeper understanding, you can learn more from RheumatoidArthritis.org, HealthCentral, Medical News Today, Mayo Clinic, NCBI Bookshelf, and WebMD.