[Histonet] cross contamination[Scanned]

Kemlo Rogerson Kemlo.Rogerson <@t> elht.nhs.uk
Mon Jan 17 07:06:34 CST 2005


Obviously, I am as aware of the dangers inherent in producing H&E's, as only
up to recently have I been preparing them since I was a pup. Certain carry
over I concede, the most desperate being on the processing machine, cannot
be eradicated, but that which can, ought. 

I think my point is that there may a be certain baseline, below which, you
may not ever pass. But if you eradicate those you can control, then you can
concentrate on those you can't. Innovative changes, I'm sure, can be
introduced by the scientific Staff and Manufacturers for the reduction of
carry over on machines. As for forceps? What ever happened to the habit of
flaming forceps to incinerate carry over on them? I know alas, health and
safety!!!

Personally I will be having a zero tolerance on carry over and for those of
my Staff reading this Listserv, my intentions are as Terry suggests. Both
CPA, GLP and the ISO's concentrate on quality management systems and I see
no reason why the 'cutter-up', the 'embedder', the 'sectioner', the 'floater
out' and the Q/C person are not identified. That was my intention in my last
Lab and that is my intention in this. If you don't know who is doing what
and when, then how can you audit the system? It's really not that difficult
to do, for a good Manager. In fact I'm an advocate of the team system which
allows each team the autonomy of producing a finished product that they
'own' and they can Q/C and order up deeper sections, if appropriate, and
some special stains previously agreed with the Pathologist. For example
PAS's on 'inflammatory' skins, etc. I remain staggered that some BMS's
cannot recognise basic tissue and at least some disease processes; maybe you
taught me too well Terry, the traits of the master come out in the student,
don't they?

I agree the water bath is the most common culprit and it accounted for most
of the BCC's I managed to get on your sections of a wart. 

Kemlo Rogerson
Cellular Pathology Manager
East Lancashire Hospitals NHS Trust
DD. 01254-294162
Mobile 0774-9754194
 

-----Original Message-----
From: Marshall Terry Dr, Consultant Histopathologist
[mailto:Terry.Marshall <@t> rothgen.nhs.uk] 
Sent: 17 January 2005 12:30
To: Kemlo Rogerson; Scholz, Stephen J.; Histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] cross contamination[Scanned]

Well Kemlo, I regard carry-over as inevitable, not necessarily a failing.
To prevent it you would need new instruments and cutting board for each
specimen.
Each specimen would need to be processed individually in new reagents.
Each specimen would need to be floated out in a cleaned water bath with
fresh water.
To be sure to be sure, a new forceps would be used for each specimen
embedded.

In short, the system of block specimen processing, using processing to cover
"the lot", is incapable of producing carry-over free results.

Were there to be a perceived increased or unacceptable (yes, I know none is
"acceptable") amount of carry-over, that is a different matter.

Finding out where the carry-over occurred is nothing to do with logging and
IR1s.
Indeed, probably the commonest place is the water bath. 
Do *you* in your lab keep a record of who floated out each and every
specimen?


Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire
 England
        terry.marshall <@t> rothgen.nhs.uk

-----Original Message-----
From: Kemlo Rogerson [mailto:Kemlo.Rogerson <@t> elht.nhs.uk]
Sent: 17 January 2005 11:57
To: Marshall Terry Dr, Consultant Histopathologist; Kemlo Rogerson;
Scholz, Stephen J.; Histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] cross contamination[Scanned]


Depends how you sell it to Staff. You are too intelligent not to understand
the benefit of logging errors so that you can detect trends. 

My feelings are that mistakes are bad enough but if you can learn from them
then they have fulfilled at least a positive function. Very hard concept for
Medical Staff and BMS to accept; that we all make mistakes, but systems can
be changed to trap these errors. But the errors need to be quantified and
recorded; I had problems trying to get Staff to accept that they fallible
and change their working practices to account for that.

Carry over, logically, only occurs at two or three points in the procedure.
Not rocket science to find out which bit of the system is failing, is it? 

Kemlo Rogerson
Cellular Pathology Manager
East Lancashire Hospitals NHS Trust
DD. 01254-294162
Mobile 0774-9754194
 

-----Original Message-----
From: Marshall Terry Dr, Consultant Histopathologist
[mailto:Terry.Marshall <@t> rothgen.nhs.uk] 
Sent: 17 January 2005 11:36
To: Kemlo Rogerson; Scholz, Stephen J.; Histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] cross contamination[Scanned]

I have only done the few cases  I consider "iffy". 
Logging all seems to me a senseless and futile flogging of techs
(irrespective of what I "should" do).

Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire
 England
        terry.marshall <@t> rothgen.nhs.uk

-----Original Message-----
From: Kemlo Rogerson [mailto:Kemlo.Rogerson <@t> elht.nhs.uk]
Sent: 17 January 2005 09:07
To: Marshall Terry Dr, Consultant Histopathologist; Scholz, Stephen J.;
Histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] cross contamination[Scanned]


Do you log it as an incident using IR1?

-----Original Message-----
From: Marshall Terry Dr,Consultant Histopathologist
[mailto:Terry.Marshall <@t> rothgen.nhs.uk] 
Sent: 14 January 2005 16:36
To: Scholz, Stephen J.; Histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] cross contamination[Scanned]

This is my practise. It is not held out to be perfect, but is honest.

If it's very obvious, as in a case yesterday with a colonic gland sticking
onto the surface of a piece of skin, I ignore it in all respects.

If less than an expert might misconceive it, I mention it. E.g. "a fragment
of endometrium, which is clearly a cross-over from another patient is
noted."

The crunch comes when you suspect it might be from another patient but you
can't know it. There is no easy way out of this one - you have to tell it as
it is.  Then wait for the "can't you do a test?" - "would immunochemistry
help?" - "can you do DNA testing" - "what do I tell the patient" and dozens
more possible witless comments or questions.

As to the language, cross-over or cross contaminant seems to cover any of
cutting board, processing and water bath contamination. 
If you can see it in the block you can be more specific, but there is little
point to being so.

Luckily, the bad scenario happens infrequently.
The worst scenario, where the cross-over is not recognised or suspected
seems even less frequent, and of course, can only be suspected in
retrospect.


Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire
 England
        terry.marshall <@t> rothgen.nhs.uk

-----Original Message-----
From: Scholz, Stephen J. [mailto:Stephen.J.Scholz <@t> osfhealthcare.org]
Sent: 14 January 2005 15:41
To: Histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] cross contamination


Hello all;

I have a question for the masses regarding cross contamination in surgical
specimens.  I would like know how others are handling situations when a
small fragment from one specimen gets embedded with a different case.
(probably stuck on  forceps)  When it is obvious upon reading the slide that
the fragment doesn't belong does the Histologist remove it?  Does the
Pathologist comment in the Path Report and what is the common language used
(debris, cross-contaminate, ect)?  What is done from the Pathologist
perspective when the contaminate tissue is similar but logic dictates that
it doesn't belong with that case. Again, is it mentioned in the report and
what language is used to state the Pathologist believes there is incorrect
tissue fragments with the case?

I eagerly await your replies,


Stephen J. Scholz HT(ASCP)
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