Dionne,
    I think that they really just want to see that you are making an effort
to provide a negative control. This question can be so overthaught. One
could easily spend 50% of their run on negatives. That would waste time and
money and wouldn't really aid diagnosis.
    On the other hand it could be totally under thought too. Minimal
negative controls can lead to a false positive slipping through. That would
not be good either. If there is some attempt made that is somewhat sound I
don't think anyone would cite a lab for it. (Please someone correct me if I
am wrong there)
     Actually you could have a perfect negative control policy but you would
then get gacked a policy on treating waste DAB :-)
Amos Brooks

----- Original Message -----
From: "Dionne Roberge" 
To: "Histonet" 
Sent: Thursday, July 11, 2002 10:36 PM
Subject: CAP-negative controls


> Dear Histonetters,
> I have many people asking how the negative controls for
Immunohistochemistry
> are being done by the professional community.   The CAP checklist,
> ANP.22570, requires a negative control for each antibody.  Are we using a
> negative control against every primary antibody used in the test or are we
> talking about the specie of the secondary in the detection system?  It
also
> discusses the pretreatments are to match as well.
> So, how many labs can spare the necessary resources for multiple negative
> controls?  For example, we have one case where five antibodies are
> requested.  Since I am devils advocate, I have two that are polyclones and
> three that are monoclones.  One of the polys is enzyme treated, the other
> has no pretreatment.  The monos, one gets a high pH retrieval method, the
> other a citrate, the other gets none.  So are we doing five negative
> controls here?
> I bring this to the table because so many people want to know how to
handle
> this.  I have had the opportunity to visit many labs and all have their
own
> way and own interpretations of this.
> We need to have this clarified to provide consistency in testing and good
> standard of patient care and lab practice.  It would be nice to hear all
> points of view, laboratorians, pathologists, and those who have dealt with
> being inspected closely for this item, as well as those who have been
> inspectors and how they have handled this issue.
> I know this is a delicate item, but let's remain open minded.  We can make
a
> positive difference here as a united professional group.
> Thank you in advance for the support and dedication.
>
> Dionne A. Roberge, HT(ASCP), QIHC
> Technical Service Representative
> DAKO Cytomation
> 800.400.3256 x5544
> dionne.roberge@dakocytomation.com
>
>