HLA-B27 Testing Questions
sniderd at fhs.csu.McMaster.CA
Wed Sep 8 09:09:31 EST 1999
We run the B-D HLA-B27 test routinely now as a screen test. We do
approximately 200 tests per month, as a regional test center. In the
initial stages we ran 2-300 samples with parallel serologic
histocompatibility testing. This established a "gray-zone" surrounding the
B-D positive/negative cutoff, in which we found almost all of the B7 and
other cross-reactions, as well as the very rare (<< 1%) false negatives.
We now only send about 5% (gray-zone) of our samples for serologic/molecular
typing. A comparison to the Lambda One antibody in the "gray-zone" was
also done. This antibody performed well in ruling out B7 cross-reactions.
However, it was not cost effective to add it to the screening protocol.
We run occasional positive controls (1 or twice a month). They are always
positive, because they are selected from known patients in the
Hope this helps.
Denis Snider Ph.D., F.C.A.C.B.
Dept. of Pathology and Molecular Medicine
From: Sparks, Scottie [SMTP:SSparks at unch.unc.edu]
Sent: Wednesday, September 01, 1999 12:59 PM
To: Cytometry Mailing List
Subject: HLA-B27 Testing Questions
We are interested in performig HLA-B27 testing by Flow. We are
BD's B27 Kit and it seems to work well.
Our questions are concerning controls: How often are positive
by those of you perfoming this test clinically? Do you have a way
preserve positive control blood that has worked for you?
Also, what have you learned about cross-reactions (like B7)?
Thank you in advance for your help! Scottie
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