Rheumatoid Factor (RF) is an antibody which can be measured in the blood. It is associated with the diseases Rheumatoid Arthritis and Sjogren’s Syndrome.
How the Test is Performed
Rheumatoid Factor (RF) is a blood test.
Medical Conditions and Symptoms
Rheumatoid Factor (RF) may be ordered by your doctor if you have symptoms of arthritis - painful, stiff, warm or swollen joints. It may also be a useful test when the diagnosis of Sjogren’s Syndrome is being considered. Sjogren’s Syndrome causes dry mouth, dry eyes, aching joints and muscles, and can result in lung and kidney problems.
Test Results Explained
The Rheumatoid Factor (RF) test result should not be considered in isolation, as it may be negative (normal) in people who have Rheumatoid arthritis or Sjogren’s Syndrome. It and may be falsely positive in many other conditions, including so-called connective tissue diseases, which often cause arthritis. The result needs to be interpreted in conjunction with a thorough medical assessment.
About 90% of people with Sjogren’s Syndrome and about 80% of those with Rheumatoid Arthritis will become RF Positive. The Rheumatoid Factor can test negative in the first year or so of symptoms, and become positive later. High levels of Rheumatoid Factor in patients with a clinical diagnosis of Rheumatoid Arthritis are associated with flare-ups in severity of the disease.
- Blood Test (venesection)
Also Known As