[Histonet] Formalin Fixation times for IHC samples

[mucram11 <@t> comcast.net]

I agree with Brett about the article however, a great deal of what we do in histology is empirical or just accepted as the way things are always done.  Over the past decade as IHC has become so important and time has been shortened for many laboratories the arguments about fixation are increasing.  The time tissue is in fixative should include the not only processor time but the time from grossing through processor fixation.

If the sample comes and is grossed early (mid morning) and placed in a holding container of fixative it may have different for better or worse staining than later arriving specimens. The tissue that comes in at 2PM and gets grossed in at 3PM and placed in the holding container for 30 minutes to an hour and then on the processor will often appear very different or "under fixed" in comparison.  We don't  look at those differences in time of fixation as often as we should and we are not always allowed to make up the time required in fixative.  If the specimen goes in late enough the fixation may be completed more by alcohols during dehydration than 10% NBF and this can effect staining as well.

Pam Marcum

-------------- Original message -------------- 

> Take a look at the J. Histotechnology 24:3, Sept 2001....special issue on 
> Fixation. It includes a couple of articles dealing with fixation and IHC. 
> 
> Brett 
> 
> Brett M. Connolly, Ph.D. 
> Merck & Co., Inc. 
> MRL, Imaging Research 
> WP26A-3000 
> PO Box 4 
> West Point, PA 19486 
> PH 215-652-2501 
> fax. 215-652-2075 
> e-mail. brett_connolly <@t> merck.com 
> 
> 
> -----Original Message----- 
> From: histonet-bounces <@t> lists.utsouthwestern.edu 
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of 
> ajennings <@t> unmc.edu 
> Sent: Thursday, February 24, 2005 9:06 AM 
> To: Histonet <@t> lists.utsouthwestern.edu 
> Subject: RE: [Histonet] Formalin Fixation times for IHC samples 
> 
> 
> 
> 
> 
> 
> Great timing on this topic 
> 
> I have been looking for a review article that actually puts in print the 
> data collected on over fixation or under fixation in samples that will be 
> used for IHC. To include the eventual breakdown of formalin and need for 
> 10-20 times volume for proper fixation. Is there such a paper with all of 
> information that histologist reverberate and others ignore? 
> 
> 
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