Positive:
Rheumatoid factor is positive in 70-80% of
adults with rheumatoid arthritis. A positive
result can also be seen in a number of
other conditions including: cryoglobulinemia
(very high level), SLE, scleroderma, HIV
and other infections, and also in 5% of
normal healthy adults (low level).
Negative:
A negative RF does not exclude
rheumatoid arthritis. Where there is a
strong clinical suspicion of rheumatoid
arthritis disease, anti-CCP is a more
appropriate test. Please send a new serum
sample for CCP testing. In these patients, a
negative result for RF should not delay
referral to Rheumatology
RF has no value in monitoring of disease
activity.
Additional information on rheumatoid factor and its clinical use can be found here: RF.
