A Study on the Estimation of Postmortem Interval Based on Environmental Temperature and Concentrations of Substance in Vitreous Humor

• Published in: Journal of forensic sciences Vol. 63; no. 3; pp. 745 - 751
• Main Authors: Yang, Mingzhen, Li, Huijun, Yang, Tiantong, Ding, Zijiao, Wu, Shifan, Qiu, Xingang, Liu, Qian
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-05-2018
• Subjects: Animals; Blood Urea Nitrogen; Calcium ions; Carcasses; Creatinine; Creatinine - metabolism; environmental temperature; Forensic pathology; forensic science; Interpolation; interpolation function; Magnesium - metabolism; mixed‐effect model; Models, Animal; Models, Theoretical; Molecular chains; Phosphorus - metabolism; Postmortem Changes; postmortem interval; Potassium - metabolism; Rabbits; Reproducibility of Results; Temperature; Vitreous Body - metabolism; vitreous humor; forensic pathology; postmortem interval; interpolation function; forensic science; vitreous humor; environmental temperature; mixed-effect model
• ISSN: 0022-1198; 1556-4029
• DOI: 10.1111/1556-4029.13615

A method to determine postmortem interval (PMI) based on environmental temperature and the concentrations of vitreous humor (VH) molecules were explored. Rabbit carcasses were placed in a chamber at 5, 15, 25, or 35°C, and 80–100 μL of VH was collected with the double‐eye alternating micro‐sampling method every 12 h. A Roche DPPI biochemical analyzer was used to measure the concentrations of six substances in VH samples. The interpolation function model and mixed‐effect model were employed for data fitting to establish equations for PMI estimation. The concentrations of K+, P, Mg2+, creatinine (CRE), and urea nitrogen (UN) exhibited an upward trend with increasing PMI in all temperature groups, while the concentration of Ca2+ showed a downward trend. Validation results using K+ and Mg2+ ions revealed that the mixed‐effect model provided a better estimation than the interpolation function model using the data from our experiment. However, both models were able to estimate PMI using temperature and VH molecule concentrations.