title: Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.
abstract: Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.
authors.affiliation: Institute of Legal Medicine, University of Bern, Switzerland. dra@irm.unibe.ch
authors.forename: M N
authors.initials: MN
authors.lastname: Hochmeister
authors.forename: B
authors.initials: B
authors.lastname: Budowle
authors.forename: O
authors.initials: O
authors.lastname: Rudin
authors.forename: C
authors.initials: C
authors.lastname: Gehrig
authors.forename: U
authors.initials: U
authors.lastname: Borer
authors.forename: M
authors.initials: M
authors.lastname: Thali
authors.forename: R
authors.initials: R
authors.lastname: Dirnhofer
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D001826:Body Fluids / Q000737:chemistry; D002415:Cats; D002417:Cattle; D004285:Dogs; D005260:Female; D005554:Forensic Medicine / Q000379:methods*; D006736:Horses; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011934:Reagent Strips / Q000737:chemistry; D012661:Semen / Q000737:chemistry*; D013552:Swine; D014659:Vasectomy
chemical_list: D000911:Antibodies, Monoclonal; D011934:Reagent Strips; D017430:Prostate-Specific Antigen