[Histonet] Re: HER2 fixation time

Dr. Hadi Yaziji ancillarypath <@t> mac.com
Thu Jan 24 11:26:34 CST 2008


Let me state this one more time: deviation from the standard range of  
exposure to each of the TP components needs to be validated. You have  
the responsibility to show that the level of signal remains the same  
compared to the standard time in melted paraffin.

If you don't have documentation to this effect, then you are in  
violation of the guidelines. If your CAP inspector approved your  
method, it's because they are not adequately trained to evaluate your  
assay compliance.

Hadi Yaziji

On Jan 24, 2008, at 12:14 PM, Kari Bradshaw wrote:

> I agree fully.  We have two VIP's.  One is set Friday night to process
> overnight and the tissue sits in paraffin until Monday morning.  The
> other processor is set Saturday morning to run an overnight process  
> and
> those tissues sit in paraffin until Monday morning as well.
> Kari Bradshaw
> Anatomic Pathology Manager
> Lower Columbia Pathologists
> 1217 14th Ave
> Longview, WA 98632
> 360.425.5620
> kbradshaw <@t> lcpath.com
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Rene J
> Buesa
> Sent: Thursday, January 24, 2008 8:47 AM
> To: ancillarypath <@t> mac.com; histonet <@t> lists.utsouthwestern.edu
> Subject: Re: [Histonet] Re: HER2 fixation time
> Not if you set the instrument to start EXACTLY when you want. You will
> have the tissues in melted paraffin more time, or you can extend the
> dehydration times. You can do a lot of things all preventing longer
> fixation in NBF. Modern TP are very flexible instruments and I have no
> data that reflects any deleterious effects for the tissues' reactive
> qualities or sectioning characteristics after being in melted paraffin
> for long periods of time.
>  René J.
> ancillarypath <@t> mac.com wrote:
>  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
> ==============================
> 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
> www.vitromolecular.com
> www.ancillarypath.com
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> Message: 18
> Date: Thu, 24 Jan 2008 09:57:05 -0500
> From: "Richard Cartun"
> Subject: Re: [Histonet] HER2neu Fixation times
> To: "Ramona Turner" ,
> 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
> 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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