Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.
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.
Hochmeister
M N
MN
Institute of Legal Medicine, University of Bern, Switzerland. dra@irm.unibe.ch
Budowle
B
B
Rudin
O
O
Gehrig
C
C
Borer
U
U
Thali
M
M
Dirnhofer
R
R
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
D000911:Antibodies, Monoclonal; D011934:Reagent Strips; D017430:Prostate-Specific Antigen