['To conduct a pilot study to test whether or not prostate specific antigen (PSA) and/or PSA-positive cells can be detected and characterized in semen specimens archived in aldehyde fixative.', 'Specimens from 12 men were examined, six before elective vasectomy and six undergoing infertility evaluation. Fixed semen elements were assessed immunocytologically using monoclonal antibodies against PSA and leucocyte common antigen, CD 45, as a control.', 'PSA was detectable in the semen from the fertile men as amorphous protein and contained within round vesicles (prostasomes). Semen from men undergoing infertility evaluation contained a greater variation in detectable forms and amount of PSA than the specimens from the fertile men, including PSA associated with some nonspermatozoal cells (NSCs).'] Is prostate specific antigen detectable in formalin-fixed semen?