Rheumatoid Factor:
Immune Complex Causes Inflammation

Rheumatoid factor is an antibody that is measurable in the blood. This test is part of the arthritis panel because rheumatoid factor is not usually present in a normal individual. It is commonly used for the diagnosis of Rheumatoid arthritis. Almost 80% of adults with rheumatoid arthritis have the presence of rheumatoid factor. This percentage is much lower among children with juvenile rheumatoid arthritis.

The rheumatoid factor antibody attaches to a substance in the body called immunoglobulin G (IgG), thus forming a molecule known as an immune complex. The immune complex can activate various inflammatory processes in the body. Rheumatoid factor can also be present in patients with other conditions including connective disease (such as Systemic Lupus Erythematosus) and infectious diseases (such as infectious mononucleosis, parasites, hepatitis, syphilis, and tuberculosis).