[Histonet] IHC Validation:

[Joelle Weaver]

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: craigak12 <@t> gmail.com
> Date: Fri, 29 Aug 2014 10:29:15 -0700
> To: Histonet <@t> 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
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