RE: [Histonet] Re: Ohh the pain (replacing formalin)

From:"Shawn Leslie"

It's a real hassle changing from either...We had originally used Anatec's Prefer but because  HER2Neu is acceptable only on formalin fixed tissue we had to change to formalin...that's when the nightmares began...Everything had to be work up again, H&E..specials, immunos......we had warned the Doc's that there will be reduced quality using formalin instead of Prefer but were told that we had to change and that they will have to accept the quality difference...that was fine and good until the first batch of slides came out and they freaked.....we were told to try this and to try that.....after a while no one knew what was going on because procedural changes were being done on an hourly basis....You could imagine the chaos in the lab.....All I can suggest is that if you have to change either way do it in a organized, systematic and scientific way otherwise everyone will regret it ...I guarantee it.....

Shawn Leslie
Scientific Research Manager
Anatomic Pathology
University of Florida
School of Veterinary Medicine
352-392-2235 ext 4555

>>> "Douglas D Deltour"  9/27/2007 12:15 PM >>>
Teri, don't be surprised. Let's just say that I can not go into detail about
the reasoning behind this. I am aware of all of the validation that is
involved in this task. At least I hope I can get the "I told you so" in
before I am kicked out the door. :)   

Douglas D. Deltour HT(ASCP)

-----Original Message-----
[] On Behalf Of Johnson,
Sent: Thursday, September 27, 2007 9:26 AM
Subject: [Histonet] Re: Ohh the pain (replacing formalin)

Douglas, if it is your Pathology group pushing you to go to non-formalin
fixative, I'm quite surprised. Pathologists are accustomed to making
diagnoses based on formalin-based artifacts. In a lab I worked in (in a
galaxy far, far away) we did the "Folger's crystals replacement"
experiment, replacing all the GI and prostate biopsy formalin fixative
with zinc formalin. I thought the pathologists were going to have a
major meltdown. The nucleoli were more prominent in all the cells, and
that freaked them out. We effectively changed what the cellular
structure looked like (even mild cellular changes can be a
diagnostically significant).

Disregarding the FDA issue and interlaboratory issues already raised
(quite valid points!), if you change what fixative you are using, the
cells will look different. And while that is not an insurmountable issue
for pathologists, it does take getting used to.

One possible substitute is glyoxal. Anatech provides this commercially
in a fixative called "Prefer". It is supposed to provide formalin-like
morphology with heightened immunoreactivity. Remember - ALL your
immunohistochemistry staining will have to be redone. ALL OF IT. It is
optimised  using formalin, and changing the fixative changes the
structure of the proteins. Some immunos may work better, some may not
work as well, some may no longer require antigen retrieval, some may
require a different retrieval method.

Do you get any consultation material (outside blocks) from other
institutions for second opinion? If so, and you need to do staining of
any kind (H&E, special stains, and IHC), you will need to optimise your
staining of that material back to formalin. Your non-formalin controls
will be useless.

I'm not saying this is an impossible task. It will be difficult and seem
impossible until it's all worked out. It takes a tremendous amount of
effort and energy to make the switch, and above all, the pathologists
should have a major stake in how their samples will be fixed, processed,
and stained. Their reputation depends on it. Their patient's diagnosis
also depends on it.

If you want to turn your attention to making formalin safer, there are
ways of doing that. That's fodder for another post altogether.

Good luck!

Teri Johnson, HT(ASCP)QIHC
Managing Director Histology Facility
Stowers Institute for Medical Research
1000 E. 50th St.
Kansas City, MO 64110

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