More on RE: [Histonet] carryover on slides

[Gayle Callis]

Terry makes an excellent point here.  If this is the type of carryover
problem one is experiencing - some of these tricks may help.  

1.  Take a clean kimwipe (NOT kleenex tissues!), lay it flat on top of
waterbath and skim this quickly across surface.  Surface floaters of the
larger variety aka carryover's will attach to kimwipe.  Do this BETWEEN
blocks or at least each case. A waterbath that is FULL to the brim with
water is easier to skim! and, in my estimation, pick up a section.  

2.  Keep your BARE fingers out of the water to prevent exfoliating cells
from skin out of water.  These ugly little clingons show up on slides and
on top of tissue sections. If your cells keep showing up in an excessive
manner, wear gloves without powder.  A good microtomist should be a clean
freak and keep hands above the waves! 

3.  One lab I worked in insisted that tissue samples be staggered to have a
cancer case? sandwiched between a noncancer case or some other tissue
sample so the blocks were spaced away from each other during sectioning.
This really didn't work all the time! What if all you had in one day's work
was cancer cases!??  When I pointed out the fallacy of this method, they
still insisted. At 03:00 PM 1/20/2004 -0000, you wrote:
>Surely all are examples of carryover.

4. Keep your waterbath scrupulously clean, soap and hot water, whatever it
takes. 


>Carryover is anything that "didn't ought to be there" and has come from
another specimen.
>It must be difficult to monitor, and the most difficult (i.e. impossible)
is the like-to-like tissue carryover, that is to say, a bit of A's
endometrium appearing on B's slide.
>Cut-up and water bath are the most likely origins, and can be minimised by
scrupulous cleanliness.
>
>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: Gayle Callis [mailto:gcallis <@t> montana.edu]
>Sent: 20 January 2004 14:45
>To: Vickroy, Jim; Histonet <@t> lists.utsouthwestern.edu
>Subject: Re: [Histonet] carryover on slides
>
>
>Could you define carryover?  Do you mean cells, tissue fragments, stains
>from one staining dish to another?  
>
>At 07:40 AM 1/20/2004 -0600, you wrote:
>>Has anyone ever seen any articles on what is an acceptable rate of carryover
>>on routine slides?  We have been monitoring our carryover rate and our
>>pathologists wondered if anyone had ever seen a study on carryover rates.
>>
>>
>>James R. Vickroy BS, HT (ASCP)
>>Technical Supervisor, Surgical Pathology
>>788-4046
>>vickroy.jim <@t> mhsil.com
>>
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>>
>Gayle Callis
>MT,HT,HTL(ASCP)
>Research Histopathology Supervisor
>Veterinary Molecular Biology 
>Montana State University - Bozeman
>PO Box 173610
>Bozeman MT 59717-3610
>406 994-6367 (lab with voice mail)
>406 994-4303 (FAX)
>
>
>
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Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology 
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)