Paraformaldehyde Fixation of Cells method or protocol. This fixation method is good for cells labeled by fluorochrome-conjugated antibodies to membrane antigens.  It will stabilize the light scatter and labeling for up to a week in most instances, allowing you to be more flexible in scheduling cytometer time.  Furthermore, it inactivates most biohazardous agents, so it is important from a safety standpoint as well. Iowa University.

Protocol: Paraformaldehyde Fixation of Cells