Application of the human trypsinogen 2 detection kit “AP Check” for human fecal identification

Abstract

Feces can serve as direct evidence in criminal investigations, as it may be intentionally left at a crime scene or mixed with food or other substances for the purpose of harassment. However, the current fecal examination process faces several challenges. In this study, we examined the possibility of detecting human trypsinogen 2 in feces using the AP Check (AP), a detection kit typically employed as an adjunct diagnostic tool for acute pancreatitis. The results of the study demonstrated that human trypsinogen 2 could be detected in dried human feces, as well as in aged fecal samples and those exposed to high temperatures. Although false-positive reactions due to sample pH and cross-reactivity with semen and primates require caution, the human fecal identification using AP is rapid, simple, and less affected by sample preservation conditions. Therefore, it is considered that human fecal identification using AP can be applied to forensic examination practices.