[Histonet] Reprocessing tissue

kemlo kemlo <@t> f2s.com
Mon Mar 24 04:31:28 CDT 2008

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

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.

----- 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 

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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