HLA-B27 Testing Questions

Snider Denis 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
histocompatibility lab.

Hope this helps.


Denis Snider  Ph.D., F.C.A.C.B.
Associate Professor
Dept. of Pathology and Molecular Medicine
McMaster University

	-----Original Message-----
	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
controls run
	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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