[Histonet] cross contamination Scanned]

Mon Jan 17 07:49:51 CST 2005

Stephen, Kemlo and Terry, I have noted the brisk and important dialogue going back and forth as it concerns
"cross over" contamination from one specimen to another. Indeed, we all recognize the issue of "error" and the need to have a "zero defect" system.  Deming, who is famous for his concept and teaching of management systems
 that promote "quality" production, defined "quality circles" as a method of promoting dialogue among production units to identify and FIX production problems. We (and include myself), are an ad hoc group in pursuit of that excellence. 
The problem is best dealt with by understanding the "chain of custody" from patient to slide. The responsibility for "getting it right" is distributed over the entire chain of custody...beginning with the patient. The
patient is the "owner" of the "chain", all of the transaction "links" add one to the other, and the longer the
chain the greater is the opportunity of failure. FIRST, failure opportunity occurs  in the collection site selected by the physician. SECOND, in the labeling, THIRD, in the storage and transport, FOURTH, in the aliquot sampling and the instruments of the grossing station, FIFTH, cassette label and security, SIXTH processing fluids and paraffin, SEVENTH, at the embedding station, EIGHTH, the microtome blade and apparatus, NINTH, the water bath and related instruments, TENTH, the cover slip station and media, ELEVENTH, slide labeling, TWELFTH, ( I can't think of it, but it must be there !)
If you wish to see something scary....take up the "droppings" from the bottom of any processing fluid or paraffin and examine them under the microscope. "vegetable soup" of specimens. 
The remedy is procedural alertness to the links in the chain. Detection is an experienced and alert histotechnonogist or pathologist. 
In reporting, it is a good idea to identify the contamination on the report.  Best procedure ,if possible, is to resample the specimen and repeat the examination.  A bit awkward but it will stand up best in COURT. 
I do not often step up to the bat but this is one of my "pet" concerns. At some future NSH meeting I would enjoy meeting each of you to continue the dialogue.  It's worth a lecture demonstration and if invited I might 
take up that cause ! 

J.B.McCormick,M.D. FCAP,(father of Tissue-Tek )

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu]On Behalf Of Marshall
Terry Dr,Consultant Histopathologist
Sent: Monday, January 17, 2005 6:30 AM
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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