Rheumatoid factor (RF)

Why this test?

• To diagnose rheumatoid arthritis and Sjogren's syndrome, as well as to distinguish them from other forms of arthritis and diseases with similar symptoms.
• For the diagnosis of autoimmune diseases (together with tests for antinuclear antibodies, C-reactive protein, ESR).

In what cases is it prescribed?

• With symptoms of rheumatoid arthritis: pain, heartburn, swelling, and limitation of joint mobility, nodular thickenings under the skin.
• A repeat analysis may be necessary if the results of the first test were negative, but the symptoms of the disease persist.
• With symptoms of Sjogren's syndrome.

Test information

Rheumatoid factor is an autoimmune antibody, an immunoglobulin protein (IgM), produced by the body's immune system. Autoantibodies attack one's own tissues, mistaking them for foreign ones. Although the nature of rheumatoid factor is still poorly understood, its presence is an indicator of inflammatory and autoimmune processes. Rheumatoid factor analysis is indispensable for confirming the of "rheumatoid arthritis" and "Sjogren's syndrome" diagnoses (a positive result in 75% and 60-70% of cases, respectively).

However, it can be used to detect a number of other diseases, such as chronic bacterial, viral and parasitic infections and some types of cancer.

 In addition, it can indicate diseases of the lungs, liver, and kidneys.