Rheumatoid Factor (RF)
Rheumatoid factor is an antibody targeting the Fc portion of IgG and is positive in most patients with rheumatoid arthritis. It is not specific and can also occur in Sjogren syndrome, cryoglobulinemia, chronic infections such as hepatitis C and endocarditis, and in some healthy older adults. Higher titers correlate with more aggressive rheumatoid disease.
5 providers include this
Autoimmune Markers
<14 IU/mL, Weakly positive:14-40 IU/mL, Positive:>40 IU/mL
What is Rheumatoid Factor (RF)?
Rheumatoid factor is an antibody targeting the Fc portion of IgG and is positive in most patients with rheumatoid arthritis. It is not specific and can also occur in Sjogren syndrome, cryoglobulinemia, chronic infections such as hepatitis C and endocarditis, and in some healthy older adults. Higher titers correlate with more aggressive rheumatoid disease.
Why It Matters
Elevated in 70-80% of rheumatoid arthritis cases. Also positive in other autoimmune diseases. Used for diagnosis and prognosis.
Which Providers Test Rheumatoid Factor (RF)?
Full Provider Comparison
| Provider | Includes | Annual Cost | Biomarkers |
|---|---|---|---|
 Superpower | ✓ | $199 | 100+ (150 with ratios) |
 WHOOP Advanced Labs | — | $349 | 65 |
 Labcorp OnDemand | — | $398 | 40+ |
| — | $486 | 40+ | |
| — | $449 | 288 | |
| ✓ | $349 | 100+ | |
| — | $829 | 54 | |
 Function Health | ✓ | $365 | 160+ |
| — | $250 | 65 | |
| — | $495 | 80+ | |
| — | $895 | 100+ | |
| — | $1950 | 130+ | |
| ✓ | $375 | 95+ | |
| — | $Varies | 75+ | |
| — | $190 | 100+ | |
| — | $99 | 50 | |
| — | $124 | 60 | |
| — | $349 | 130+ | |
| — | $349 | 80+ | |
| — | $375 | 85 | |
| — | $700 | 128 | |
| ✓ | $99 | 100+ |
Frequently Asked Questions
What is Rheumatoid Factor (RF)?
Rheumatoid factor is an antibody targeting the Fc portion of IgG and is positive in most patients with rheumatoid arthritis. It is not specific and can also occur in Sjogren syndrome, cryoglobulinemia, chronic infections such as hepatitis C and endocarditis, and in some healthy older adults. Higher titers correlate with more aggressive rheumatoid disease.
What is the optimal range for Rheumatoid Factor (RF)?
The standard reference range for Rheumatoid Factor (RF) is <14 IU/mL, Weakly positive:14-40 IU/mL, Positive:>40 IU/mL. Optimal ranges may differ based on individual health goals and expert recommendations.
Which blood test providers include Rheumatoid Factor (RF)?
5 out of 22 blood testing providers include Rheumatoid Factor (RF) in their panels. This biomarker has limited availability.
What category does Rheumatoid Factor (RF) fall under?
Rheumatoid Factor (RF) is categorized under Autoimmune Markers. This category includes biomarkers that help assess related aspects of health and wellness.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed:2026-04-12