From the Guidelines
An isolated elevated rheumatoid factor (RF) without clinical symptoms does not require specific treatment and is not diagnostic of rheumatoid arthritis or any other autoimmune condition. The presence of RF can be seen in various conditions, including other autoimmune diseases, chronic infections, malignancies, and even in approximately 5% of healthy individuals, especially older adults 1. According to the 2010 ACR/EULAR classification criteria for rheumatoid arthritis, a low positive RF or low positive ACPA is scored as 2, while a high positive RF or high positive ACPA is scored as 3 1. However, the absence of clinical symptoms and other diagnostic criteria makes it unnecessary to initiate treatment solely based on an elevated RF.
Clinical Approach
When encountering an isolated elevated RF, the recommended approach is clinical monitoring rather than immediate intervention. Patients should be evaluated for symptoms such as:
- Joint pain
- Swelling
- Morning stiffness
- Fatigue
- Other signs of inflammatory disease If the patient remains asymptomatic, follow-up testing in 6-12 months may be appropriate to monitor for changes. The level of RF elevation and the presence of other autoantibodies like anti-CCP (cyclic citrullinated peptide) antibodies provide more diagnostic specificity 1.
Referral to a Rheumatologist
If symptoms develop or RF levels significantly increase over time, referral to a rheumatologist would be appropriate for comprehensive evaluation and potential treatment planning. It is essential to consider the patient's overall clinical presentation and not rely solely on the RF level for diagnosis or treatment decisions 1. The 2010 ACR/EULAR classification criteria for rheumatoid arthritis emphasize the importance of considering multiple factors, including joint involvement, serologic findings, acute phase reactants, and duration of symptoms, to accurately diagnose and manage rheumatoid arthritis.
From the Research
Isolated Elevated Rheumatoid Factor
- Isolated elevated rheumatoid factor can be found in patients without rheumatoid arthritis, as stated in the study 2
- The presence of a rheumatoid factor and/or anti-citrullinated protein antibody is consistent with a diagnosis of rheumatoid arthritis, but it is not exclusive to this disease 3
- Many normal people have a positive test for rheumatoid factor but do not have rheumatoid arthritis, even among those with extensive musculoskeletal pain ['false-positive' results] 2
- About a third of rheumatoid arthritis patients have negative tests for rheumatoid factor or anti-cyclic citrullinated peptide antibodies, and more than 40% have a normal erythrocyte sedimentation rate or C-reactive protein at presentation ['false-negative' results] 2
Laboratory Tests and Rheumatoid Arthritis
- Laboratory tests, such as complete blood count (CBC), can provide valuable information about disease activity and prognosis in rheumatoid arthritis 4, 5
- CBC-derived inflammatory biomarkers, such as neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), and red cell distribution width (RDW), can assess disease activity and response to treatment in rheumatoid arthritis 4, 5
- Patient questionnaire scores and RAPID3, an index of physical function, pain, and patient global estimate of status, can identify incomplete responses to methotrexate more effectively than erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) 2
Disease Activity and Prognosis
- Disease activity scores and indicators, such as RDW, MPV, and PLR, can be associated with disease activity in patients with rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis 5
- SII (systemic immune-inflammation index) can be considerably higher in rheumatoid arthritis and ankylosing spondylitis patients compared with controls, but not in systemic lupus erythematosus patients 5
- NLR (neutrophil-to-lymphocyte ratio) can rise dramatically in systemic lupus erythematosus patients compared with controls, but did not change much in rheumatoid arthritis and ankylosing spondylitis patients 5