AI-Powered · Free · Instant
Interpret Your Rheumatoid Factor Results
Enter your RF value below and get an instant, free AI interpretation — a plain-English explanation checked against WHO/IFCC reference ranges.
Medical Disclaimer
This AI-generated interpretation is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results may vary based on individual health factors not captured here.
Always consult a qualified healthcare professional before making any health decisions. Read full disclaimer →
Loading interpreter…
Rheumatoid Factor Normal Ranges
Rheumatoid Factor (RF) is an autoantibody — typically IgM — directed against the Fc portion of IgG immunoglobulin.
| Reference Range | Unit | Notes |
|---|---|---|
| 0 – 14 | IU/mL | Negative <14 |
Common Causes of High RF
Rheumatoid Arthritis (RA) — most common clinical indicationSjögren's syndrome (often very high RF)SLE (systemic lupus erythematosus)
Common Causes of Low RF
Approximately 20–30% of RA patients are "seronegative" — RF negative — especially early in diseaseNegative RF does not exclude RA (seronegative RA exists)
Want the full clinical guide to Rheumatoid Factor?
Reference ranges, causes, symptoms, preparation, and FAQs.