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