Re: [Histonet] negative IHC controls

Negative reagent controls are supposed to be consistently negative. That's the point!

The notion of not performing negative reagent controls on patient samples for IHC, because they have always been consistently negative in the past, is equivalent to the equally bizarre notion of removing the airbags, seat belts, child restraints and other safety equipment from your automobile, because you have not yet had an accident and have therefore never used them.

Consultant Technologist

----- Original Message -----

Sent: Wednesday, October 08, 2003 4:56 PM

Subject: [Histonet] negative IHC controls

I would like to get a feel for how many out there are running negative control slides for IHC.

In our lab we do just a handful of antibodies and initially I had been running a negative control slide with each patient slide. After much discussion with our pathologists, we decided to omit these negatives (which were conistently negative) and continue to just run a positive control with each primary antibody for the run. We use the Dako autostainer and prediluted primaries. The decision to stop running negatives also coincided with Dako's decision to sell the negative control sera separately from the primaries (they used to come packaged together). Perhaps I assumed that discontinuing to pair these reagents together meant that few labs were using the negatives.

Anyhow, after having reviewed the last QMPLS (Canada) survey committee comments, I believe the committe would like a negative control run with each patient tissue slide in order to evaluate background (they have used NCCLS guide pages as reference). Incidentally we weren't a part of the survey due to a technicality.

Any help or advice would be appreciated.