Keri - RF and sed rate

[Guest guest]

The rheumatoid factor level (it's more appropriate to refer to it as the

RF level or RF titer, not " RA level " as certain doctors do, because this

test is not specific to rheumatoid arthritis (RA)) is supposed to be

used to help make an RA diagnosis, not monitor the disease.

The " sed rate " is the erythrocyte sedimentation rate (ESR) which is a

measure of inflammation. This test can be used to monitor RA.

Below is a link below to a excellent article entitled " Clinical Utility

of Common Serum Rheumatologic Tests. "

http://www.aafp.org/afp/20020315/1073.html

Two relevant quotes:

" In patients with rheumatoid arthritis, the RF titer generally

correlates with extra-articular manifestations and disease severity. RF

testing may have prognostic value in these patients. However, RF titers

are not helpful in following disease progression. Once a patient has a

positive RF result, repeating the test is of no value. "

and

" The ESR is a means for staging rheumatoid arthritis, rather than a

major diagnostic criterion. The ESR value tends to correlate with

clinical disease activity and to parallel such symptoms as morning

stiffness and fatigue, although joint examination is far more useful in

assessing synovitis. The sensitivity of an elevated ESR value is

approximately 50 percent in patients with signs of rheumatoid arthritis.

However, the specificity of an elevated ESR is quite low, limiting its

use as a diagnostic test. "

[ ]

> Is the RA level the same as the sed rate? Why would the doc be

> watching this " level " so closely?

> I'm a little confused I guess.

> Thank You

> Keri