Yes, ultimately up to lab director/medical director/pathologist as to
determination of specificity, selectivity, and if you have enough examples, and
the staining reactivity conforms to the "intended clinical use" during their
assessment and hopefully approval of your protocol. I have used some TMAs with
success, especially if you make with your own in-house processed tissues. I try
to strongly favor using several expression levels of normal and diseased tissue
whenever possible that reflect what it will be used for in the patient test
tissues. If single sections, I try use both expected or known negative and
positive tissue both normal and diseased , when practical for the first
validation set when I get past optimization. For small adjustments I may need
only a few more confirming positives- up to MD in my situation. I also have
polymer detection, but I still like some negatives for me. Some people may not
feel this is necessary, and the pathologist may not need the negatives ( using
internal controls), but this helps me, so I do it to feel more confident in my
results as I present the slides for review. I don't see why you couldn't use
internal negatives, if you clarify what tissue element acts as the internal
negative in the tissue type in the validation summary and SOP. Basically, for
amount or # to stain, I follow the CAP guidelines ( newer ones), for well
characterized. For markers with specific guidelines for validation and
correlation, I follow the CAP guidelines exactly. Setting up the process/SOP s,
I used the CLSI guidebook on validation of IHC assays. Both resources (CAP &
CLSI) have been very helpful for me. That is what has been working for me, I
hope this helps.
Joelle Weaver MAOM, HTL (ASCP) QIHC
> From: craiga...@gmail.com
> Date: Fri, 29 Aug 2014 10:29:15 -0700
> To: Histonet@lists.utsouthwestern.edu
> CC:
> Subject: [Histonet] IHC Validation:
>
> How do most people validate IHC? I want to create a tissue microarray. I
> wanted to use an average of 6-8 positive tissues.
>
> Is it necessary to validate using negative tissues when there is always an
> internal negative control in all tissue sections. Now with new polymer
> detection systems there is not background, etc.
>
> Is IHC validation ultimately up to the discretion of the laboratory director?
>
> Please advise. Thx-
>
> Sent from my iPhone
> _______________________________________________
> Histonet mailing list
> Histonet@lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet
_______________________________________________
Histonet mailing list
Histonet@lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet
