Hospital wet mount examination for the presence of sperm in sexual assault cases is of questionable value.

Many protocols for the examination of sexual assault victims include the preparation of vaginal wet mount slides to determine whether sperm are present and if so, whether the sperm are motile. We have reviewed findings in 501 case reports to compare the efficiency of sperm detection on wet mounts to subsequent crime laboratory results of sperm searches on vaginal swabs. Sperm were detected on wet mounts in only 41% of cases in which sperm were detected in the crime laboratory.