Is It Arthritis or Rheumatoid Arthritis? Understanding RF Test Ranges and Treatments

An RF (Rheumatoid Factor) test is crucial for distinguishing between different forms of arthritis, including rheumatoid arthritis (RA). High levels of rheumatoid factor in the blood most often relate to autoimmune diseases such as rheumatoid arthritis and Sjogren syndrome.

While rheumatoid factor (RF) levels above the normal range can indicate autoimmune conditions like rheumatoid arthritis, not everyone with high levels of rheumatoid factor will develop an autoimmune disorder. The exact triggers of the autoimmune response that leads to rheumatoid arthritis are not completely understood.

The normal range of RF is typically considered to be 0 to 20 IU/ml, commonly referred to as RF negative. However, some definitions consider a rheumatoid factor greater than or equal to 15 IU/ml as elevated. This discrepancy underscores the complexity of diagnosing conditions associated with rheumatoid factor.

Rheumatoid factors (RF) are not exclusive to rheumatoid arthritis (RA); they are also found in a variety of other pathologies, including autoimmune and non-autoimmune diseases, and even in a small percentage of healthy individuals, particularly in the elderly.

Symptoms prompting an RF test may include fatigue, occasional low fevers, loss of appetite, and issues beyond joint pain, such as dry eyes or mouth, subcutaneous nodules, or anemia. Additionally, RF tests are part of the diagnostic process for other autoimmune disorders, including Sjögren syndrome.

Individuals with rheumatoid arthritis often exhibit elevated levels of erythrocyte sedimentation rate (ESR), or C-reactive protein (CRP), which may signal an inflammatory process in the body. Common blood tests also look for rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Imaging tests may be employed as well.

The causes of rheumatoid arthritis are believed to be multifactorial, involving a combination of genetics, hormones, and environmental factors. About 80% of people with RA test positive for rheumatoid factor (RF). Lifestyle factors, like high blood cholesterol—a risk factor for coronary artery disease—can also be addressed through diet and the consultation of a nutritionist.

For a comprehensive diagnosis and management plan for rheumatoid arthritis, consult the extensive information provided by the Mayo Clinic, Medical News Today, and the Rheumatoid Arthritis Organization. You can also learn more about rheumatoid factors in the StatPearls article from the NCBI Bookshelf and the Cleveland Clinic overview of rheumatoid arthritis.