Hypostasis and Time Since Death

Hypostasis is a common postmortem change, whose presence or absence is used by forensic pathologists as a means of determining the approximate time of death. This assessment plays a primary role in Italian forensic practice, but blanching of hypostasis is still estimated only on the basis of subjective impressions. To understand how forensic pathologists test livor mortis on the crime scene and during forensic daily practice in Italy, an inquiry was made into lividity testing. Subsequently, with the aim of proposing a more objective approach, a study on postmortem lividity was performed; 101 cadavers were analyzed, and the color of hypostasis was measured by a colorimeter. Different conditions of time and pressure on hypostasis were tested. Linear regression analysis was performed to determine the relationship between postmortem interval and the color of the skin after a predefined intensity and duration of pressure. Herein we propose a novel operative instrumental protocol using new, more standardized conditions for the analysis of hypostasis, thus providing pathologists with a more rigorous approach to postmortem interval estimation.