ELISA is more sensitive than standard immunoelectrophoretic methods and more cost-effective than other methods of semen analysis. Several experiments were conducted to validate the ELISA procedure, determine the best threshold for casework analysis, and ascertain the sample dilution factor most appropriate for forensic casework. The results consistently showed a sensitivity of less than 1 ng/mL PSA. Numerous domestic contaminants and body fluids were tested; none gave a false-positive result. However, samples contaminated with detergent did yield false-negative results. Some poorly preserved samples did not give positive results when expected. Nonetheless, the authors found the ELISA method to be highly sensitive, specific, and efficient in identifying semen samples, particularly because this PSA ELISA allows hundreds of samples to be tested simultaneously. 3 tables, 3 figures, and 16 references