Rheumatoid Factor (RF)-Reference Range

Rheumatoid factor is an antibody that is detectable in the blood of approximately 80% of adults with rheumatoid arthritis.

The normal range for rheumatoid factor is less than 14 IU/ml. Any result with values 14 IU/ml or above is considered abnormally high, elevated, or positive.

High levels of rheumatoid factor may indicate:

  • Rheumatoid arthritis (RA)
  • Rheumatoid nodules
  • Rheumatoid lung disease

It should be noticed that a negative RF test does not rule out RA. About 20% of people with RA will have very low levels of or no detectable RF.

Keywords: Rheumatoid Factor (RF)

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