[Histonet] Re: HER2 fixation time

ancillarypath <@t> mac.com ancillarypath <@t> mac.com
Thu Jan 24 10:19:42 CST 2008

I agree with Rich, and it's good to hear that some colleagues have  
started their own mode of cross-validation.

If you choose to deviate from the upper fixation limit of 48 hours,  
you will ONLY be at default if you do not have evidence (with  
documentation) that raising the upper fixation limits to 72 or 96  
hours has no detrimental effects on the results. The CAP will  
eventually increase the upper limit to 72 (or hopefully 96) hours once  
there is solid evidence that is ok to do so.

Rene's suggestion to put the instrument on delay is not a valid  
solution. As long as the tissue is sitting in formalin in the  
instrument while it's on delay, it's still being fixed. This issue was  
discussed at the ASCO/CAP meeting.


Hadi Yaziji, M.D., Medical Director
Vitro Molecular Laboratories,
President, Ancillary Pathways
7000 SW 62nd Avenue, Suite Penthouse-C
Miami, FL 33143
Tel 305.740.4440
Fax 786.513.0175

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Message: 18
Date: Thu, 24 Jan 2008 09:57:05 -0500
From: "Richard Cartun" <Rcartun <@t> harthosp.org>
Subject: Re: [Histonet] HER2neu Fixation times
To: "Ramona Turner" <mona_diane <@t> hotmail.com>,
	<histonet <@t> lists.utsouthwestern.edu>
Message-ID: <479860F2020000770000A527 <@t> gwmail4.harthosp.org>
Content-Type: text/plain; charset=US-ASCII

Personally, I would not initiate any drastic changes at this point.   
Keep in mind that these are guidelines; however, you must validate  
your testing if you are going to follow other fixation guidelines.  I  
think everyone knowledgeable with this issue knows that the problem is  
with underfixation, not overfixation.  I recently pulled tumor out of  
formalin after 8 months of fixation and the IHC was still "3+" and the  
FISH showed beautiful amplification (ratio of 10.0).  I hope that once  
the scientific evidence is evaluated, these guidelines will be  
changed.  Major expense is being incurred here unnecessarily.  How is  
your concordance between IHC and FISH for the detection of HER2?  If  
it's not broken, don't try to fix it.  Our "ad-hoc" committee on IHC  
standardization is meeting in Santa Barbara on Sunday and I hope this  
issue will be discussed.


Richard W. Cartun, Ph.D.
Director, Immunopathology & Histology
Assistant Director, Anatomic Pathology
Hartford Hospital
80 Seymour Street
Hartford, CT  06102
(860) 545-1596
(860) 545-0174 Fax

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