What is the Normal Range for a Rheumatoid Factor (RF) Test?

Rheumatoid Factor (RF) is a significant antibody in diagnosing rheumatoid arthritis and other autoimmune diseases. The normal range for Rheumatoid Factor levels can vary depending on the laboratory and the assay used. Most laboratories consider a range from 0.0 to 14.0 as normal, and levels higher than this range are generally considered abnormal.

Rheumatoid factor was first described in relation to rheumatoid arthritis in 1940. For decades, a positive rheumatoid arthritis test, which indicates a higher level of rheumatoid factor in the blood, was used to diagnose those with symptoms of the condition. Approximately 80% of adults with rheumatoid arthritis have detectable rheumatoid factor in their blood, making it a common test in the diagnostic process.

However, it’s important to note that high levels of rheumatoid factor in the blood can be related to other autoimmune diseases, such as Sjogren syndrome. Additionally, some healthy individuals may have detectable rheumatoid factor, and conversely, people with autoimmune diseases might have normal levels of this factor.

Understanding lab test results, including Rheumatoid Factor levels, is crucial for managing Rheumatoid Arthritis effectively. Normal levels for men range from 0-15 mm/hr to 0-20 mm/hr and for women from 0-20 mm/hr to 0-30 mm/hr, depending on age. It’s also possible to have symptoms of rheumatoid arthritis with normal RF test results, in which case further tests may be required for a diagnosis.

For more detailed information on Rheumatoid Factor and its implications, you can refer to sources like RheumatoidArthritis.org, MedicineNet, Mayo Clinic, Medical News Today, Hospital for Special Surgery, MedlinePlus, Verywell Health, and Johns Hopkins Arthritis Center.