[Histonet] negative controls with IHC

[lwuerges]

I have a question regarding negative controls for a manual immunoperoxidase procedure.  Do you use a neg control for each antibody used with each block? or one neg control per block regardless of how many antibodies for that block.  The latter is what I was told, but the first seems more likely on account of  each antibody may be treated differently with some needing antigen retrieval--obviously the contol should receive identical treatment.  What is the usual neg control protocol?
Thank you.
Lisa Wuerges