first. welcome to world of histology.
Let's begin at the grossing table- all grossers are trained to wipe off the
table after each case- but that doesn't mean floaters can't happen, but the
incidence is low
third- embedders should have been taught to clean the embedding area after
each case and at the end of the day, but this is a good source for
contamination. You can see this is the block.
fourth- the cutters should wipe off their waterbaths after each block. This
probably is the most likely source of contamination. I've inspected some
labs where one waterbath was just covered with previous ribbons, attached to
the side and floating on the waterbath.
fifth- in my experience, it is highly unlikely that floaters came from the
stainer just by the shear movement of the slides and water.
The bottom line is that everyone needs to be neat and clean and be
meticulous. Remember, cleanliness is next to Godliness.
I had a testicular seminoma where no matter what we did, floaters still were
on cervical bxs and endometrial bxs. The medical and I decided that we
would handle cases like these separately. They were processed, embedded, cut
and stained separately. Once the case was completed, we changed all the
solutions on the tissue processor and stainer. Who ever cut the blocks had
to dismantle their knife holder and microtome to clean it thoroughly. A pain
in the butt, but was a necessary evil.
I hope this helped a little. Good luck.
Joe The Toe
----- Original Message -----
From: "Michelle McCoy"
Sent: Thursday, September 06, 2007 12:57 AM
Subject: [Histonet] Floater sources
>I was reading some of the old archived messages on floaters, and being
> somewhat new to the field of histotechnology was curious about how
> can be attributed to a particular tech who performed work on the block.
> example, couldn't other sources of contamination be from the automatic
> stainer, processor carryover (cassette not completely closed/or if closed,
> friable tissue through the slats eg if sponge not used on larger
> In some previous labs I've worked in- floaters were quickly attributed to
> the cutter, embedder or grosser and might result in a "write up". If the
> floater is seen in the block how can you differentiate if it came from the
> grosser carryover/embedder carryover/processing carryover/unsigned
> re-embedder/or even possibly even client carry over between patients or
> different specimen types of the same patient.
> And if it is not in the block --differentiating between the
> stainer (I've seen specks of tissue debris in automatic stainers/ sections
> falling off the slides and into the reagents etc). Obviously all should be
> done to minimize the factors, but I'm just not clear how a single source
> pinpointed and potentially blamed for the event (depending on the lab
> policy). Thanks for any ideas on this.
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