NCJ Number
218712
Date Published
April 2003
Length
4 pages
Annotation
This study used the Seratec PSA (prostate-specific antigen) Semiquant semiquantitative membrane test in order to estimate the PSA extraction efficiency in testing for the presence of seminal fluid.
Abstract
The study found that the PSA extraction efficiency when analyzing liquid extracts from dried semen solutions was sufficiently low to limit their usefulness. The findings suggest that a more efficient extraction process would be beneficial when applying these types of membrane tests to forensic science applications. The yield from common forensic substrates was 1 percent or less of the estimated total available PSA in the samples. In this study, liquid semen sample dilutions were found to be near the 4ng PSA/ml internal standard value. Forensic semen stains and swabs were then prepared with known quantities of these semiquantified semen samples. Semen from both a vasectomized individual and a nonvasectomized individual were diluted to 1:1,000,000 with sterile water. Swabs were prepared from the dilutions by using approximately 150ml of solution per swab. The swab was allowed to saturate and then to air-dry. Stains were also prepared on clean cotton cloth using 500ml of the semen dilutions and then allowed to air-dry. Duplicate extractions of approximately one-third of each swab (vasectomized semen only) were performed in 250ml of sterile water for 2 hours at room temperature. After centrifugation for 1 minute at 13,000g, 200ml of the supernatant was removed and tested with the Seratec PSA membrane (x2) and the OneStep ABA card p30(x1). 6 references