At our institution, because of lack of space limitations, our IHC is in a different room, located across the hall from our histology lab.  At the time IHC was first incorperated, this was to a great advantage because of all the activity and noise going on in the lab (plus we had to work with Dee (hahahaha)) the quiet improved the results!!! It was just too easy to make a human error when doing them by the hand method.  But now that we have automated, I see no reason why it could not be incorporated if you have the space.  In fact, there is redesigning talk of our entire lab going on at this time, and we are concidering this option.
Hope this helped!

Lynette                       sorry Dee!!!!  hahahahahah

Hurley Medical Center
Flint, MI