[Histonet] Responses to IHC CAP Validation question

[Mike Pence]

 I know you keep the paper work showing what you have done, but do you
keep slides also?

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of McMahon,
Loralee A
Sent: Wednesday, April 28, 2010 2:02 PM
To: thisisann <@t> aol.com; histonet <@t> lists.utsouthwestern.edu
Subject: RE: [Histonet] Responses to IHC CAP Validation question


Any inspection that I have undergone we have used the 25 to 30 case
rule.  Except for the Er/Pr//Her-2.  We use closer to 50 cases.  We also
use a TMA to make our lives easier.  The TMA contains known positives
and known negatives. 
In cases of t-cell or b-cell markers or cytokeratins.  25 to 30 cases is
easy.  But when you are validated for more hard to find markers (SV-40)
then fewer cases is acceptable.  We always throw in a slide that we know
will not stain for sv-40 like a tonsil - then you can say it has
specificity. Any inspector that I have come across is usually
understanding of this.  But I am sure that there are exceptions to
this.........especially if they are not familiar with
immunohistochemistry. 



Loralee McMahon, HTL (ASCP)
Immunohistochemistry Supervisor
Strong Memorial Hospital
Department of Surgical Pathology
(585) 275-7210
________________________________________
From: histonet-bounces <@t> lists.utsouthwestern.edu
[histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of
thisisann <@t> aol.com [thisisann <@t> aol.com]
Sent: Wednesday, April 28, 2010 2:47 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Responses to IHC CAP Validation question

The following is one respone I rec'd:

1.  I asked CAP who told me that they do not currently have a guideline
on validating but that they recommend what is in the following book:
Quality Management In Anatomic Pathology, Promoting Patient Safety
Through Systems Improvement and Error by Raouf E. Nakhleh, MD & Patrick
Fitzgibbons, MD editors sold by CAP ! Chapter 8- Quality Management in
IHC That is what we follow. I. Get a new antibody and optimize it with
your positive control. II. Once optimized you need to run it on cases
expected to be positive (how many?) "a suffient size ..." III. Must also
be run on cases expected to be negative. (how many? IV. In a situation
where you cannot expect a lot of cases or such a case has never been
presented in your lab, then you must say just that. (ex. some of the
hormones we just use a pituitary)







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