[Histonet] Reprocessing tissue

Joe Nocito jnocito <@t> satx.rr.com
Mon Mar 24 18:23:00 CDT 2008

um, no. Deparaffinizing, dehydrating and then going back through paraffin is 
too harsh on the tissue. For argument sake, try it out. I've been doing this 
for years and haven't had a problem.

----- Original Message ----- 
From: "kemlo" <kemlo <@t> f2s.com>
To: "'Joe Nocito'" <jnocito <@t> satx.rr.com>; "'Lynn Wade'" 
<lynnw <@t> nf.sympatico.ca>; <histonet <@t> lists.utsouthwestern.edu>
Sent: Monday, March 24, 2008 4:31 AM
Subject: RE: [Histonet] Reprocessing tissue

> Um no, Joe.....
> If you do that then the xylene/ wax impregnated tissue won't mix with the
> formalin (as you say), anyway it's fixed that's not the issue, so why 
> waste
> time fixing again?. Melt the blocks down, as you say, then pass through
> xylem until they are transparent, well as transparent as the poor 
> processing
> allows. You then place into 100% alcohol until properly dehydrated denoted
> by the xylene making them transparent (trial and error I'm afraid as you
> don't know how dehydrated they are). When clear impregnate with wax as
> before; you may note that the tissue becomes more brittle because of
> increased length of time in reagents and especially wax. But less so than
> Joe says as you are not doubling the processing time which must impact
> adversely on ICC.
> Have fun.
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Joe Nocito
> Sent: 24 March 2008 00:46
> To: Lynn Wade; histonet <@t> lists.utsouthwestern.edu
> Subject: Re: [Histonet] Reprocessing tissue
> Lynn,
> ThermoFisher Scientific and Ventana Medical Systems have systems that you
> can barcode the paperwork, which then makes bar-coded blocks which then
> makes bar-coded slides. In each step, the barcodes are read to ensure that
> the correct specimen is being processed. If there is a mis-match, an alarm
> beeps alerting the user.
> For reprocessing tissue, we just melt the blocks down, place the tissue 
> back
> in the block and put the blocks in formalin to be processed with new 
> cases.
> Whatever area did not process the first time will take up the formalin, 
> and
> graded alcohols. When the tissues reach xylene, the paraffin is dissolved
> and everything get infiltrated. The areas that have been processed will
> repel the formalin and alcohols until they are immersed into xylene. I 
> find
> this method is a lot easier on the tissues, especially if IHC is performed
> on them later.
> As far a an electronically created list of blocks going into a processor, 
> I
> haven't heard of any.
> Hope this helps.
> Joe
> ----- Original Message ----- 
> From: "Lynn Wade" <lynnw <@t> nf.sympatico.ca>
> To: <histonet <@t> lists.utsouthwestern.edu>
> Sent: Sunday, March 23, 2008 6:31 PM
> Subject: [Histonet] Reprocessing tissue
> Hi folks:
> I am wondering if anyone has had an incident in Patholgy lab where on the
> tissue processor the reagents got switched inadvertantly. For instance, 
> the
> 80% alcohol was inadvertantly placed in the last 100% alcohol slot and 
> thus
> water was reintroduced into the tissue just before xylene, clearing amd
> paraffin.
> Has anyone had this occur and how did you recover the tissue?
> Also, can anyone tell me if there is such a processor that has a system 
> that
> can be used to log in the cassette numbers that are put onto the processor
> so that in the event of some incident such as we had the retrieval of the
> exact specimens can be done electronically?
> And lastly can anyone tell me if they have a fully barcoded system whereby
> path specimens arrive barcoded and every document, slide and block has a
> barcode that allows for tracking of the tissue at all times?
> We are looking at processes and trying to close some gaps.
> Lynn Wade
> Program Manager, Safety & Quality Management
> Medical Services & Diagnostics
> Eastern Health
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