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The positive identification of seminal fluids in sexual assault crimes is considered crucial evidence to determine whether a sexual act occurred or not. However, current presumptive methods lack specificity and sensitivity. Confirmation of semen by microscopic examination of spermatozoa is laborious, time consuming, and can sometimes lead to negative or inconclusive results. Here we report the use of the Proximity Ligation Real-Time PCR (PLiRT-PCR) assay as an attractive and promising confirmatory method for the identification of semen and sperm proteins using two polyclonal antibodies, Prostate Specific Antigen (PSA) and Sperm-Specific Protein (SP10), respectively. PLiRT-PCR, relies on protein recognition by pairs of proximity probes (antibody-DNA conjugates) that give rise to a ligated DNA strand. The ligated DNA strand is then amplified and detected by qPCR., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Detection of semen biomarkers in vaginal fluid can be used to assess women's recent exposure to semen. Quantitative tests for detection of prostate-specific antigen (PSA) perform well, but are expensive and require specialized equipment. We assessed two rapid immunochromatographic strip tests for identification of semen in vaginal swabs., Study Design: We tested 581 vaginal swabs collected from 492 women. Vaginal secretions were eluted into saline, and PSA was measured using the quantitative IMx (Abbott Laboratories, Abbott Park, IL, USA) assay. Specimens were also tested using the ABAcard p30 test (Abacus Diagnostics, West Hills, CA, USA) for detection of PSA and RSID-Semen test (Independent Forensics, Hillside, IL, USA) for detection of semenogelin (Sg)., Results: Vaginal swab extraction using saline was compatible with direct assessment of vaginal swab eluates using ABAcard for PSA detection, but not for Sg detection using RSID. The rapid PSA test detected 91% of specimens containing semen compared to 74% by the rapid Sg test., Conclusion: Investigators are urged to optimize vaginal swab specimen preparation methods for performance of RSID or other tests to detect semen components other than PSA. Previously described methods for PSA testing are not uniformly applicable to other tests., (Copyright 2010 Elsevier Inc. All rights reserved.)