[Cytometry] Distinguishing Surface vs. Cytoplasmic staining

Prashant Sharma prashant.sh at gmail.com
Tue Jul 14 13:06:30 EDT 2009

Dear List members,

I had a rather basic question on flow and would be glad to have help: Will a
cell positive for a certain antigen on surface staining always show that
antigen as positive after fix-and-perm cytoplasmic staining? Even if the
antigen is not present in the cytoplasm?

The reason I ask (this biologically unlikely question) is because it was
suggested somewhere that one way to exclude a false positive CD41 / CD61 on
blasts due to platelet adhesion would be to simply perform cytoplasmic
staining instead of surface.

My take on this is that since the platelets or their membranes are adherent
to the cell surface, they would (most likely) still be there after the fix /
perm steps and would therefore still give a positive signal.

Would you say this last assumption is correct? Or to extrapolate the
question, if we are doing cytoplasmic staining for an antigen, are we, in
effect, doing a "cytoplasmic or surface or both" stain?


Prashant Sharma, MBBS, MD, DNB
Senior Resident, DM student
Hematology Department
All India Institute of Medical Sciences
Ansari Nagar, New Delhi, India.

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