I have stained Cytology slides for immuno, on the Es, the nexes, and the Gen
2, I have used acetone fix then air dried, for 15 min, I have pre-fixed in
formalin 15 min, and have used etoh fixation, the reason for the different
fixations depended mostly on the antibody requested  and the conditions the
spec sheets stated the antibody liked.
I have stained blood smears for example with formalin fixation to hold the
malignant
cells , but the water in the formalin has gotten rid of the blood cells , so
therefore no
additinal peroxidase block needed  and no background, this for example was
great with the cytokeratins. I have used paraffin slides for controls only
because the ability to obtain cyto controls is limited, optimally though it
really should be similiar fixed tissue or smears, this as you know is not
always available. I have stained cyto spins that are alcohol fixed for er/pr
and had great results, a little tissue loss but not much.
feel frre to contact me and I can walk you thru more protocols if need be.
                                                Dana Dittus
                                               Histology Supervisor
                                             Abington Memorial Hospital
                                               1-215-481-2609