A comparative analysis of accuracy and sensitivity in semen testing: ABAcard p30™, RSID Semen™, and Seratec PSA™.

Abstract

Confirmatory semen tests are used to determine the possible presence of semen in an evidence sample. Current test kits target proteins like PSA and semenogelin, but these markers can yield false positive results when identifying potential semen evidence. This study evaluated the sensitivity and specificity of three rapid immunochromatographic semen detection kits: RSID™ Semen, Seratec™ PSA, and ABAcard™ p30. These kits are marketed as confirmatory tests for semen. Test samples included serial semen dilutions, bodily fluids, and materials previously shown to cause false positives. All tests were performed according to manufacturers' protocols. Combined test results indicated a 9.4% false positive rate. False positives occurred across all kits with absorbent hygiene products (e.g., tampons, menstrual pads, and diapers). RSID™ Semen failed to detect semen in a 1:10,000 dilution and when mixed with dirt, indicating a 3% false negative rate and a false positive rate of 9%. ABAcard™ p30 produced false positives with female urine. While Seratec™ PSA demonstrated the highest sensitivity with only a 1% false negative rate, its false positive rate (12%) was the highest observed. ABAcard™ p30 exhibited superior performance with the lowest false positive rate (6%) and a false negative rate of 2%. While most forensic labs have moved away from using these kits as confirmatory tests, it is vital to emphasize why reporting their results as definitive semen evidence is problematic. These tests cannot confirm semen presence and should not be used alone as confirmatory evidence in forensic reports.