Identification of sperm and non-sperm male cells in cervicovaginal smears using fluorescence in situ hybridization: applications in alleged sexual assault cases.

The identification of spermatozoa or constituents of seminal fluid is critical in the evaluation of alleged sexual assault victims. However, failure to identify sperm and/or elevated levels of acid phosphatase can occur for a variety of reasons. Molecular techniques, such as molecular cytogenetic analysis offers new approaches to improve on the identification of male cells in alleged sexual assault cases. Fluorescence in situ hybridization (FISH) with a Y chromosome specific DNA probe was applied to archival cervicovaginal smears from 41 alleged sexual assault cases to identify Y-bearing (male) cells. FISH identified Y-bearing sperm and non-sperm cells in 78% of the cases previously confirmed to have sperm. FISH also identified Y-bearing non-sperm male cells in 39% of the cases in which cytology did not detect spermatozoa; in one of these instances, it also detected sperm. Cervicovaginal acid phosphatase levels, determined at the time of the cervicovaginal smears, were also compared with the presence or absence of Y-positive cells. Application of this technique can detect non-spermatozoic male cells in routine cervicovaginal smears of sexual assault victims.