RE: [Histonet] Sponge problems in processing

From:"Stapf, Ross"

At my former hospital, we had a major problem with biopsies being fried
once.  It turned out to be a combination of things.

1. The techs had skipped a day changing that processor.
2. And most importantly a PA over the weekend had added a 3rd rack to
the processor.  The problem was it was a VIP 1000 and it isn't made to
use 3 racks.  So the top blocks were only half covered at best with

At the time we didn't know about the sponge carryover.  What we couldn't
figure out was why some of the blocks done on Friday looked just as bad
as the blocks the PA had added over the weekend which were not fully
covered with solution.  Later when I heard about this sponge carryover
it made since.  There were over 120 blocks on that processor.  All of
them were biopsies in sponges.  The solutions were already being pushed
to the limit because someone had decided they could wait until Monday to
change the processor.  Add in the third rack and it was a recipe for

Most of the blocks were severely compromised even after reprocessing.
About 1/4 were unreadable.  It was a mess. 

Sponges can be used effectively for years and years.  You just have to
be aware of this carryover problem and keep the processor changed
properly and not overload it.  The culture of the lab can't allow any
skimping on changing the processor as this affects everything.  I now
prefer to use a much larger processor than physically necessary for
biopsies so that there is a larger volume of fluid to compensate for the
carryover when using sponges.

Here they use the mesh cassettes for most biopsies and rarely use
sponges so this is not a problem. 

Now mesh cassettes and air bubbles are a whole other problem that I get
to deal with on occasion.

Ross M Stapf
Histopathology Manager
Baylor University Medical Center
3500 Gaston Ave.
Dallas, TX 75246

214-820-4110 fax

-----Original Message-----
[] On Behalf Of Brennan,
Sent: Wednesday, April 07, 2004 8:33 AM
Subject: RE: [Histonet] Sponge problems in processing

We have been using these sponges for years on Sakura VIP processors with
vacuum,agitation, etc without any problems of solvent carryover or
artifacts in the tissue.

Liam Brennan
Belfast City Hospital

-----Original Message-----
From: S Ladd []
Sent: 07 April 2004 13:58
To: Marshall Terry Dr, Consultant Histopathologist
Subject: RE: [Histonet] Sponge problems in processing

Good point about the vacuum. Also, with or without sponges there is
going to be carry over (in the tissue, in the chamber, in the hoses,
clinging to the casettes etc.) I was trying to do the math... How much
95% alcohol (and ultimately how much water?) would be carried over to
the xylene station, if there were 200 mL of 95% alcohol retained, each
station contained 4000 mL of liquid and there were 3 100% alcohol
stations in between? I got a headache trying to figure out the dilutions
and I gave up. The point is, if we have an appropriate processing
protocol with multiple stations of alcohols, xylenes and paraffins and
we make use of vacuum and agitation and change our reagents often, then
I think these fancy new processors should be able to deal with the carry
over of liquid retained in the sponges. We put 200 cassettes on our
processor, with 50-75% of the cassettes containing sponges and UNLESS
the P/V and agitation gets mistakenly turned off, our specimens are
appropriately processed. Of course, this is just my opinion and if I had
the time, I would do a couple little experiments... Sharron University
of South Florida

-----Original Message-----
[]On Behalf Of Marshall
Terry Dr,Consultant Histopathologist
Sent: Tuesday, April 06, 2004 11:21 AM
To: Steven E. Slap; Gayle Callis; Gudrun Lang;
Subject: RE: [Histonet] Sponge problems in processing

OK. 200 ml. of liquid retained, with 100 blocks.
However, with a vacuum processor, is that not all "sucked away"?

BTW, should it sound otherwise, I hate the things (but am stuck with

Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path  Consultant
Pathologist  Rotherham General Hospital  South Yorkshire  England

-----Original Message-----
From: Steven E. Slap []
Sent: 06 April 2004 16:14
To: Gayle Callis; Gudrun Lang;
Subject: Re: [Histonet] Sponge problems in processing

Hi HistoNetters

I agree with Gayle, and the other posters who pointed out that sponges
carry over 1ml of fluid per sponge (so, with 100 cassettes, 200 sponges,
that's a lot of carryover).

I have had a lot of success with the biopsy cassettes which Gayle refers
to, both in microwaves and in conventional tissue processors. You can
request samples from Lab Storage Systems in St. Louis by phone at (800)
345-4167 or by e-mailing Rita Lovshe at

best regards,
Steven Slap

At 10:20 AM -0700 4/1/04, Gayle Callis wrote:
>To: "Gudrun Lang" ,

>From: Gayle Callis 
>Subject: [Histonet] Sponge problems in processing
>We no longer use sponges, prefer to place tissues in tissue embedding

>(Fisher) which look like tea bags or the little nylon bags (not as easy
>handle, but thinner than sponges) and a tidge stiffer than tea bags.
>Sponges can cause artifacts in your tissues, looking like triangular
>in section.  This was published by Freida Carson in Journal of
>Histotechnology, 1980's.  Using tea bags may not be as fast during
>embedding, but speed there is a trade off for having to reprocess
>tissue samples, ho hum tedious and time consuming while patient waits.
>You analysis of problem sound correct with a poor exchange of solvents

>through sponges. If you pack cassettes super tight in basket/cassette

>holder inside processor you can impede solvent flow or if sponges are

>crammed too tight agaist tissue then lid smashed down on tissue/sponge

>sandwich - this is like having too thick a tissue in a cassette.
>There are some clever biopsy cassettes with a folding, fine mesh

>inserts fitting inside a cassette.  These may be worth a try to avoid

>sponges. I think they are available through Fisher or some other

>company who could provide free samples.  It will be interesting to see

>peoples testimonials on using these.
>There was Histonet discussion on these sponges way back in time - it

>may pay to do a search for those messages in Histonet Archives.

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