About rheumatoid factor (RF)

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UW CME Online

Laboratory Testing in the Rheumatic Diseases

Dr. C. Gardner

" Rheumatoid Factor

Rheumatoid factor is not sensitive nor specific enough to rule in or out

rheumatoid arthritis. The rheumatoid factor is present in 70-80% of

patients who have RA. This means that 20-30% of patients with RA are

seronegative for rheumatoid factor. It is most useful as a prognostic

indicator in patients with RA. People with RA who are rheumatoid factor

positive typically have a more aggressive disease. It is also useful in

confirming one's clinical impression that a polyarthritis that looks

like RA is even more likely to be RA. It is also followed in patients

with Sjogren's disease to predict the development of lymphoma.

Rheumatoid factor production may be a way for the immune system to

enlarge immune complexes to make them more easily removed by the spleen

and other immune organs.

There are a variety of other clinical conditions that are characterized

by the presence of rheumatoid factor, limiting its specificity. "

http://www.uwcme.org/site/courses/legacy/rheumlab/rafactor.php

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org