[Histonet] Contamination..processor?

Thomas Jasper tjasper <@t> copc.net
Wed Mar 24 12:31:23 CDT 2010

Hi Brandi,

Don't know if I can solve your problem...but here's a few questions.

1)You've determined that the floater (tonsil cells in this case) are in
the block.  Did you determine this because you consistently see the same
floater in the same spot, level after level, slide after slide?

2)Do you use a forceps warmer at your embedding station?  If so, have
the wells of that warmer been cleaned out lately?  It can be a source of

3)Do you have 2 processors?  If so, are you running separate programs
(on separate machines of course) for large and small specimens?  If you
can do this and you are not, you might want to consider it.

4)While it's possible you could be picking something up from your
processor, I would not be initially suspect of it.  Are you running
clean runs after processing runs?  If you are this should basically take
care of any residual tissue floaters that may have gotten out of a
(tonsil) block, or any other block for that matter. 

You embedded the GI biopsies first, so I would not suspect the embedding
center work surfaces to be a source of your tonsil floater.  Some
machines have little grooves to allow waste paraffin to drain off,
sometimes things can be trapped there.  Also, you say that the
pathologist grossed the tonsils after the GI's.  I believe you and
him/her, but was anything else grossed before the GI's?  Some type of
lymphatic tissue?  I tend to look to the grossing bench 1st for the
source of floaters because once it's done there, it shows up everywhere
else.  Also, when techs cut and embed, they have no choice but to cut
and embed whatever they're given.  There is no way to determine if what
you might be looking at is a floater.  And more often than not, when
cutting and embedding you've inherited a floater as opposed to
introducing one.

Good luck, hope this helps.

Tom Jasper

Thomas Jasper HT (ASCP) BAS
Histology Supervisor
Central Oregon Regional Pathology Services
Bend, Oregon 97701
tjasper <@t> copc.net

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of
tigger13b <@t> aol.com
Sent: Wednesday, March 24, 2010 9:41 AM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Contamination..processor?

Hello everyone.

     Today we have a problem with contamination.  The pathologist notes
cells from tonsil specimens here and there on our GI biopsy slides.  The
cells are in the block.  I'm trying to ascertain the source of the
     The grossing pathologist grossed the tonsils AFTER all GI specimens
yesterday (not source of contaminant).  We (the techs) embedded all GI
specimens first, trimmed, cut, floated and stained ALL GI specimens
BEFORE the tonsils (not source of contaminant).  The only other source
of the contamination I can think of is from the tissue processor.  We
have a Tissue Tek VIP closed processor.  Has anyone ever experienced any
problems like this?  We had a similar issue a few weeks ago.  I thought
the contaminant cells may be from a bladder tumor, which had multiple
sections submitted.  In this instance the cells showed up days work of
the bladder tumor, and in the following days work also (though the
pathologists could not say for sure the cells were from the bladder
case).  We changed our formalin solutions in the processor and the
problem did not present the next day.  We also started putting all
bladder tumor specimens in the microcassettes, to prevent tissue from
escaping.  Has anyone had any problem like this, or does anyone have any
ideas on how to prevent this in the future?  We had not seen this
problem until these past two incidences, and this tonsil problem is
particularly strange to me because we process tonsils and GI specimens
in the same workload on a regular basis and have never had this issue
before.  Any help is appreciated!  


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