[Histonet] IHC control debate

[Sebree Linda A]

Lynette,

Its not so much the positive control tissue as the antigen it's
detecting; there are antigens that are quite labile and so lose their
reactivity over time when the positive control tissue slides are stored
at room temperature.  Off the top of my head, ER, PR, Ki67, bcl-2, bcl-6
are some that come to mind...there are a number of others.  So we store
some previously cut control slides at RT and others at -20 degrees C
depending upon the antigen they will be used for.  You can find further
information regarding the more sensitive antigens in the Histonet
Archives.

Hope this helps,

Linda A. Sebree
University of Wisconsin Hospital & Clinics
IHC/ISH Laboratory
DB1-223 VAH
600 Highland Ave.
Madison, WI 53792
(608)265-6596



-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Lynette
Pavelich
Sent: Tuesday, May 26, 2009 1:16 PM
To: histonet <@t> lists.utsouthwestern.edu; fudo <@t> ufl.edu
Subject: [Histonet] IHC control debate


Hello,
I need help from all of our IHC expert guru's!  We have a debate going
on about the known positive control blocks.  All are FFPE with 8-48 hrs
in formalin.  All have been tested and have been approved for use as
positive controls.  We currently cut the positive control from the block
as needed. I have learned that some controls do start to deteriorate
over time, tonsils for example.  But, is there a list, an article,
SOMETHING that can guide me so that we can cut some of these controls
ahead of time? 
This would not only save tech time, but would further the use of our
controls.  In cutting the block, some of the good control is wasted and
some positives are hard to find. My argument is that the purchased
controls work wonderfully, even after a very long time and our improved
detection kits have improved so much over the years, it makes this
possible.

If there is no published article out there, I implore you experts to
please help us in this area.  Would also like to hear from the technical
experts from our suppliers too!  Until then, the debate continues
on!!!!!!!

Thank you!!
Lynette

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