ABSTRACT
AIM: To evaluate BioSign prostate specific antigen (PSA), a membrane test device used as a clinical aid in the diagnosis of prostate cancer, to determine whether it can be used in forensic laboratories for identifying semen stains. METHODS: Biological fluids were obtained under ethical approval from anonymous consenting donors. BioSign PSA was evaluated in terms of its specificity, sensitivity and cost to replace an ELISA (enzyme linked immunosorbent assay) method of PSA detection. RESULTS: Semen stain extracts and semen diluted 10(5) tested positive with BioSign PSA. Animal semen, other human body fluids and commonly encountered household products tested negative. Anomalous results were observed with semen-free condoms containing nonoxynol-9. The cause of these false positive results is not known. CONCLUSIONS: These results and the ease of use of the BioSign PSA kit indicate that it is a valuable addition to forensic laboratories and can adequately replace the ELISA method of PSA detection. BioSign PSA was not suitable for testing condoms for semen.
