RE: [Histonet] QC/Validation of Histo Chemicals

From:"Bonnie P Whitaker"


Don't you think what she means is more like checking a new detection system
in immuno?  You replace the whole shebang, and run a known (hopefully
multi-tissue) control and compare it to the same control stained with the
old lot.  If you changed many variables, and there was a problem, it could
be a nightmare, but most of the time everything works like a charm.

In the clinical labs that I've worked in you run validations by doing the
same patient tests and controls (the number can vary) using the reagent in
current usage, and also using the new reagent and then check the comparison
statistics to make sure the tests run with the new reagent are in an
acceptable range before the new reagent is "released" for use in the lab.

In histology, the multi-tissue control could be used to run one slide, but
producing multiple "tests" for comparison.

Bonnie Whitaker
Technical Director, Histology Laboratory
Department of Pathology and Laboratory Medicine
UT Med School
6431 Fannin
MSB 2.231
Houston, TX  77030

-----Original Message-----
[]On Behalf Of Morken, Tim -
Sent: Wednesday, September 24, 2003 10:29 AM
To: 'Barbara Stancel';
Subject: RE: [Histonet] QC/Validation of Histo Chemicals

I've never heard of anything like that in histology. Every inspection I've
been involved in has been more interested in freshness of chemicals, date of
production, documentation of who made it up, written procedures for
producing the reagents, etc. The controls run during a procedure are
supposed to "validate" whether the procedure actually works - which
validates whether the chemicals "work."

I guess that you would need to run a procedure on a control and replace only
the given chemical, leaving all others the same. If you make up all new
reagents for a procedure  then you would need to do the same for every other
chemical in the procedure. So for a stain that requires 10 chemicals, you
would need to do ten different control runs, each with only one chemical as
the variable. Sound like a lot of work for little or no real value - after
all, most of these reagents are very simple solutions that "work" all the

Tim Morken
Lab Vision / NeoMarkers

-----Original Message-----
From: Barbara Stancel []
Sent: Wednesday, September 24, 2003 4:55 AM
Subject: [Histonet] QC/Validation of Histo Chemicals

To all histology laboratories inspected by any agency:

Are you required to validate (do they work?)  chemicals such as: 1% acetic
acid, acid alcohol, dilutions of hydroquinone, Scott's Tap Water, 10% NBF,
Bouin's, aqueous solutions of sodium thiosulfate, periodic acid, sodium
borate, picric acid solutions, etc. (get my drift?)?  Do your auditors
consider the QC you do for stains and dyes as a satisfactory
confirmation/validation that an individual solutions within a procedure

I am not talking about QC of stains. In this lab that is a given...after
preparation, all stains and dyes are QC'ed and the slide is labeled and kept

as a permenent record. Auditors are wanting us to mark chemicals with a big
ole "needs approval" label. After we prove they work, we apply a big ole
"validate" label on all the bottles. We already have a labels on the
bottles. Each contains the batch number, solution, stain, date, QC date and
the person who performed the QC. The batch number is tracable on a special
sheet on which we record even more all the inventory
numbers for the chemcials, stains or dyes used in the preparation of that
solution, date prepared, date in use, date out of use, etc.

Since all our auditors are chemist or microbiologist we are trying to make
them see our point of view.  This needs approval/validation method is used
in chemistry and microbiology.

Any suggestions? (please tell me which agency audits your lab)

Histologically yours,

Barbara (who feels like I am recording my life on spreadsheets with batch
and inventory numbers!)

Barbara H. Stancel, HTL(ASCP)HT
USDA, FSIS, OPHS, Eastern Laboratory, Pathology
RRC, 950 College Station Road
Athens, Georgia  30604
phone: (706) 546-3556
fax: (706) 546-3589

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