Evaluation of Three Rapid Detection Methods for the Forensic Identification of Seminal Fluid in Rape Cases

Abstract

We sought to discover whether spermatozoa concentration and the delay between ejaculation and test influence the results of seminal fluid fast detection tests. Two hundred and twenty-seven anonymous sam ples divided into four groups (normospermia, oligospermia, azoospermia, and controls) after a semen analysis were subjected to three fast detection semen tests: Diff-Quick® fast coloration, Phosphatesmo Km Paper® for acid phosphatases (AP) detection, and PSA-Check 1® for prostate specific antigen (PSA) detection. The study was performed at three time points (0, 48, and 72 h). Unlike cytology, results obtained with AP and PSA were not influenced by spermatozoa concentration. PSA detection results remained constant up to 72 h and were more reliable after 48 h than those obtained by AP detection.

Positive prostate-specific antigen (PSA) reaction in post-mortem rectal swabs: A cautionary note

“…[1][2][3][4] Acid phosphatase (AP) paper test is another widely used detection test for seminal liquid. 5 AP is an enzyme secreted by the prostate gland, but it is not unique to the prostate and can be found in other biological fluids.…”

Relationship of spermatoscopy, prostatic acid phosphatase activity and prostate-specific antigen (p30) assays with further DNA typing in forensic samples from rape cases

“…On the other hand, additional sources of variation in casework material come from logistic information since complainant report is not necessarily infallible and during the crime the initial quantity of semen is unknown or even rape might not involve ejaculation. Also, using distinct sampling and handling procedures may cause a differential rate of degradation of semen markers [4,11,14,15].…”

“…For example, the routine and generalized use of commercially available kits as are the rapid and qualitative staining kits for APA may extend the reliability of this marker from 14 to at least 24 h following rape [11]. In addition, these kits provide the advantages of internal controls and specialized skill for interpretation is not required.…”

“…Moreover the conclusive demonstration of semen materials in rape samples by biochemical tests preceding a reliable malespecific DNA profiling still requires evaluations under real live sampling conditions. The most recommended biochemical techniques for the routine forensic analysis of rape include sperm cytology (SC), AP activity (APA) and recently PSA detection [11]. SC is a 'gold standard' or confirmatory test; in cases of oligospermic, azoospermic or vasectomized individuals APA is a screening (presumptive) test because it can be found at lower concentrations in normal vaginal secretions [12] while PSA provides a more specific marker that has been detected with immunological techniques of increasing sensitivity [13].…”

“…As expected, a delay in sampling vaginal swabs (e.g. !16 h) adversely affect detecting these markers albeit their relative stability is kept the same [4,11].…”