[Histonet] Formalin smell in the last paraffin station in vip 6 tissue tek

Cooper, Brian bcooper <@t> chla.usc.edu
Tue Nov 25 12:17:17 CST 2014

Not sure if it's the same scenario, but this happened to us once about a dozen years ago on an older version of a VIP.  Luckily, I haven't seen this again!  

One of our lab assistants loaded a basket of formalin-fixed tissues onto a processor that hadn't yet been through the clean cycle.  The machine wouldn't let him start the process, so he took the basket out and put it back into formalin to wait while he ran the clean cycle.  For that brief moment that the basket was in the retort, a bunch of residual formalin drained off the tissues and basket and mixed in with the residual molten paraffin that was left in the bottom of the retort.  Anyway, after he ran the clean cycle he started the run as usual.  8 hours later, our blocks smelled like formalin when we cut them, and they were all "mushy" in texture.   

So Sakura told us that whenever you run the clean cycle, the VIP (again, it was a really old model and I'm not sure if the technology is still the same) will attempt to draw back into the last station that was used, any residual reagent that was left in the retort before proceeding to the next reagent.  Since the last reagent had been paraffin, anything in the retort (including the newly mixed in formalin) went back into the last paraffin chamber on the VIP.  As such, the next basket of tissues were infiltrated with formalin-infused paraffin in the very last processing step.   If I recall, we had to reprocess almost all of those blocks.  

Hope this helps.   

Brian D. Cooper, HT (ASCP)CM | Histology Supervisor 
Department of Pathology and Laboratory Medicine
Children's Hospital Los Angeles 
bcooper <@t> chla.usc.edu 

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Arun Jyothi S.P
Sent: Monday, November 24, 2014 10:53 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Formalin smell in the last paraffin station in vip 6 tissue tek

Dear all
After processing in vip 6 the last paraffin has a strong odour of formalin

Have anybody experienced the same
Any ideas why it is happening.

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