Quick Facts
- Sample: Blood (venous draw)
- Fasting: Not required
- Turn-around: 1-2 business days. May take longer based on weather, holiday or lab delays.
Benefits
- Early detection of rheumatoid arthritis helps you start treatment sooner
- Convenient access with no doctor's visit required to order
- Fast results delivered confidentially within days to guide next steps
- No fasting needed—flexible scheduling fits your routine easily
- Comprehensive evaluation supports diagnosis of multiple autoimmune conditions beyond RA
Who Is This Test For?
- Adults experiencing unexplained joint pain, swelling, or morning stiffness
- Individuals with family history of rheumatoid arthritis seeking early screening
- People with suspected autoimmune disorders like Sjögren syndrome or lupus
- Anyone monitoring known RA to track disease activity over time
- Those seeking diagnostic clarity before scheduling rheumatology appointments
How It Works – Just 3 Steps
- Order online – Select your test and complete checkout securely
- Visit a lab – Get your blood drawn at thousands of locations nationwide
- Receive results – Access your confidential report online within 1-2 business days.
FAQ
What does this test measure? This test detects rheumatoid factor (RF) antibodies—proteins your immune system produces that may attack healthy tissues.
Can I have RA with a negative RF result? Yes, approximately 20–40% of RA patients test negative for RF, especially in early disease stages.
Will a positive RF result confirm rheumatoid arthritis? Not definitively—positive RF appears in other conditions and some healthy individuals, requiring clinical correlation.
Do I need to fast before this test? No fasting or special preparation is required for the Rheumatoid Factor Blood Test.
How accurate is the RF test? RF testing has sensitivity of 60–90% and specificity around 85% for RA diagnosis (NCBI 2023).
Should I take this test if I feel fine? Consider testing if you have joint symptoms or family history, even with mild concerns.
More Details
What is the purpose of this test?
The Rheumatoid Factor Blood Test detects RF autoantibodies in your blood to help diagnose rheumatoid arthritis and other autoimmune disorders. Rheumatoid factors are proteins your immune system mistakenly produces that target healthy tissues instead of pathogens. This autoimmune response causes inflammation, particularly in joints, leading to pain and damage. The test measures RF IgM antibodies through quantitative immunoassays, providing objective data about autoimmune activity in your body (Mayo Clinic 2024).
Elevated RF levels strongly suggest autoimmune disease, especially when combined with clinical symptoms like joint swelling and stiffness. The test also helps differentiate between rheumatoid arthritis and other types of arthritis, guiding appropriate treatment strategies. According to the American College of Rheumatology, RF testing remains a cornerstone biomarker for RA diagnosis and disease monitoring (ACR 2024).
Who would benefit from this test?
You may benefit from RF testing if you experience persistent joint pain, swelling, or morning stiffness lasting over 30 minutes. Individuals with symmetrical joint involvement—affecting both sides of the body equally—should consider screening, as this pattern strongly suggests rheumatoid arthritis. Family history of RA increases your risk, making preventive testing valuable even without symptoms.
People diagnosed with other autoimmune conditions like Sjögren syndrome or lupus may order this test to evaluate overlapping symptoms. The test also helps monitor disease progression in known RA patients, assessing whether treatment effectively controls autoimmune activity (Mount Sinai 2025). If you're experiencing unexplained fatigue, low-grade fever, or general malaise alongside joint symptoms, RF testing provides diagnostic clarity.
When should I order Rheumatoid Factor (RA) Blood Test?
Order this test when you notice persistent joint symptoms that interfere with daily activities or last beyond several weeks. Morning stiffness that improves with movement, especially lasting over an hour, indicates possible RA requiring evaluation. If multiple small joints in your hands, wrists, or feet become swollen simultaneously, prompt testing helps catch disease early.
Consider ordering as part of an autoimmune workup if you have unexplained fatigue, low appetite, or general unwellness alongside joint discomfort. Testing proves valuable before your first rheumatology appointment, providing objective data that accelerates diagnosis. Repeat testing may be appropriate if you're monitoring known RA or if initial results were borderline with ongoing symptoms (MedlinePlus 2024).
How do I interpret the results?
Below 15 IU/mL
- Meaning: Negative—no significant RF detected
- Typical action: RF unlikely contributing to symptoms; explore other causes
15–20 IU/mL
- Meaning: Borderline—low positive RF
- Typical action: Repeat testing and clinical correlation recommended
Above 20 IU/mL
- Meaning: Positive—elevated RF detected
- Typical action: Strongly suggests autoimmune activity; consult a rheumatologist
Above 60 IU/mL
- Meaning: High positive—significant RF elevation
- Typical action: High likelihood of RA; prompt specialist evaluation needed
Approximately 5–10% of healthy individuals over 65 test positive for RF without any autoimmune disease.
Positive RF results increase the likelihood of rheumatoid arthritis but don't confirm diagnosis alone—clinical symptoms, imaging, and additional tests like Anti-CCP antibodies provide complete assessment. Higher RF levels generally correlate with more severe RA and increased risk of joint damage. However, negative RF doesn't rule out RA, as seronegative RA occurs in 20–40% of patients (NCBI 2023).
RF elevation also appears in other autoimmune diseases including lupus, Sjögren syndrome, and scleroderma. Chronic infections like hepatitis C, tuberculosis, and endocarditis occasionally cause elevated RF. Your healthcare provider interprets results within your complete clinical picture, considering symptoms, physical exam findings, and other laboratory tests.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting or dietary restrictions are required before the Rheumatoid Factor Blood Test. You may eat and drink normally, take regular medications, and maintain your usual routine. The test requires a simple venous blood draw performed at any participating lab location.
Inform the phlebotomist about any bleeding disorders or if you're taking blood thinners, though these rarely affect RF testing. Wear comfortable clothing with sleeves that roll up easily for convenient blood collection. No special scheduling requirements exist—choose any time that fits your schedule.
How often should I get tested?
- Initial screening with symptoms: once, then follow up based on results
- Borderline or inconclusive results: repeat in 6–12 weeks with clinical assessment
- Diagnosed RA on stable treatment: every 6–12 months or as directed
- RA with changing symptoms: every 3–6 months to monitor disease activity
- Other autoimmune disease monitoring: as recommended by your healthcare provider
RF levels typically remain relatively stable once established, so frequent repeat testing provides limited value in stable patients. Your rheumatologist may order periodic RF testing alongside other markers like CRP or ESR to comprehensively assess disease activity and treatment effectiveness. Testing frequency should align with your clinical course and treatment adjustments.
Why early detection matters
Early rheumatoid arthritis diagnosis dramatically improves long-term outcomes by enabling prompt treatment before irreversible joint damage occurs. Studies show that patients starting disease-modifying therapy within three months of symptom onset experience significantly better functional outcomes and reduced disability (ACR 2024). Untreated RA causes progressive cartilage erosion and bone destruction, leading to permanent deformity and loss of joint function.
Rheumatoid arthritis affects approximately 1% of the global population, with higher prevalence in women and individuals aged 40–60. Early detection combined with modern biologic therapies can achieve disease remission or low disease activity in many patients, preserving quality of life and work productivity. Beyond joints, RA increases cardiovascular disease risk, making early intervention important for overall health protection (CDC 2025).
RF testing provides an accessible first step toward diagnosis, helping you and your healthcare provider make informed decisions about specialist referrals and treatment timing. The earlier you catch RA, the better your chances of preventing the chronic pain and disability traditionally associated with this condition.
Related tests you may consider
Arthritis #1 Baseline Blood Test Panel – Helps to screen for rheumatoid arthritis (RA), evaluate the severity of the disease, monitor treatment, and detect potential side effects of treatment.
C-Reactive Protein (CRP) Blood Test, Quantitative –Measures CRP levels to detect and monitor inflammation caused by infections, autoimmune diseases, injuries, or chronic conditions, helping doctors assess treatment effectiveness and overall health.
Complete Blood Count (CBC) and Comprehensive Metabolic Panel (CMP-14) Blood Test Panel – Used to diagnose and monitor health conditions by evaluating blood cells, liver and kidney function, and detecting diabetes.
