Hi,
    It's really easy to get something "brown" on your slides but to be
sure it is supposed to be there, the negative control is often a great
help. If there is something that looks like staining on the test slide and
it is on the negative control then you can safely ignore it because it was
obviously not put there by any antibody antigen reaction. So in effect you
can save yourself some work by running negatives .I do sympathize that
sometimes it is virtually impossible to run one on all the blocks. There
have been times I've run 50 keratins in addition to all the other IHCs.
But, on the other hand I have run cases where there was always something
staining, no matter how many times it was repeated (at the Dr's request).
When he finally saw a negative control with the same staining pattern he
said "Well gee, If I had seen this earlier I wouldn't have needed all
those other repeats!"
Smile through the pain ...
Amos Brooks

Laurie Colbert wrote:

> Is there a good reason to run a negative control on every block when
> staining IHC's?  We do a lot of keratin stains on lymph nodes from the
> same specimen (not part A, part B, etc.) and we run a negative control
> along with the keratin on every block.
>
> Laurie Colbert