Prostatic acid phosphatase. Current assessment in vaginal fluid of alleged rape victims.

Although elevated prostatic acid phosphatase activity (ACP) in vaginal fluid is compatible with recent coitus, the finding of spermatozoa in vaginal fluid is usually considered the diagnostic indicator for semen. When 80 alleged rape cases during an 18-month period were reviewed and the results of cytologic examination for the presence of spermatozoa compared with quantitative ACP determinations, the latter appeared to be a more reliable and sensitive indicator of semen. The normal range of ACP in semen, as well as persistence of ACP in vaginal fluid, was also defined. It is concluded that vaginal fluid ACP is a reliable and sensitive method for identification of semen. Furthermore, the results confirm that quantitative ACP determination of vaginal fluid specimens may substantiate the allegation of rape with respect to time.