From the Research
The normal rheumatoid factor (RF) value in females is typically less than 14 IU/mL (international units per milliliter), though reference ranges may vary slightly between laboratories. A value above this threshold may suggest the presence of rheumatoid arthritis or other autoimmune conditions. However, RF testing alone is not sufficient for diagnosis. Elevated RF levels can be found in approximately 70-80% of rheumatoid arthritis patients, but RF can also be elevated in other conditions such as Sjögren's syndrome, systemic lupus erythematosus, chronic infections, and even in some healthy individuals, particularly older adults. For this reason, RF testing should be interpreted alongside other clinical findings, physical examination, and additional laboratory tests like anti-cyclic citrullinated peptide (anti-CCP) antibodies, which offer higher specificity for rheumatoid arthritis. If RF levels are elevated, follow-up with a rheumatologist is recommended for proper evaluation and management.
Key Considerations
- The reference range for RF may vary between laboratories, so it's essential to consider the specific laboratory's reference range when interpreting results.
- RF testing is not specific for rheumatoid arthritis and can be elevated in other conditions, so a comprehensive diagnostic approach is necessary.
- The use of biologic disease-modifying antirheumatic drugs (DMARDs) has been shown to be effective in treating rheumatoid arthritis, but the choice of treatment should be individualized based on patient characteristics and disease severity 1, 2.
- Methotrexate is considered the preferred DMARD for the treatment of rheumatoid arthritis, but combination therapy with other DMARDs or biologics may be necessary in some cases 3, 1, 2.
Management
- If RF levels are elevated, further evaluation and management by a rheumatologist are recommended.
- Treatment should be individualized based on patient characteristics, disease severity, and response to therapy.
- The use of biologic DMARDs and other treatments should be considered in patients who do not respond to methotrexate or other conventional DMARDs 1, 4, 2.