[Histonet] IHC neg. controls (Friday rant)

[pruegg <@t> ihctech.net]

Patti et al,

this has been a bone of contention in IHC for some time now, the IHC
Resource Group has discussed this year after year with no viable solution
that CAP will go for, i know for a fact that many in the business save
precious tissue and run just one negative reagent control for the antibody
species and most agressive pretreatment for the batch, then take their
chances with CAP when the time comes.

Patsy

> Can someone rationalize to me the practice of running a negative control
> for
> every  antibody in an IHC workup? For example, six antibodies & six
> negative
> controls??? This makes me crazy. Just had a case, needle biopsy, where
> this
> occurred at an outside institution, and now we don¹t have enough tumor
> left
> to run more IHC & get a diagnosis. It borders on malpractice IMO.
>
> On the AP CAP checklist ANP.2270 Are appropriate negative controls used?
> The
> comment has the following (near the end):
>
> A negative tissue control must be processed for each antibody in a given
> run.  Any of the following can serve as a negative tissue control:
>
> 1.             Multitissue blocks.  These can provide simultaneous
> positive
> and negative tissue controls, and are considered ³best practice²
> 2.             The positive control slide or patient test slides, if these
> slides contain tissue elements that should not react with the antibody.
> 3.             A separate negative tissue control slide.
>
> I think it best to asses this negative tissue control on your positive
> controls that should contain negative elements. Plus, use known negative
> elements on the patient slides. The patient tissue is precious & these
> patients have undergone procedures that have associated morbidity. I can¹t
> see using up patient tissue for multiple negative controls & Having the
> patient have to undergo another procedure!
> Ok ­ I¹ll stop now.
>
> Patti Loykasek
>
>
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