This document contributes to scientific data in support of insulin death investigations and reports on a research study aimed at providing an analytical method that forensic laboratories can use to test samples for exogenous insulin and C-peptide.
The authors of this report address the lack of validated tests for exogenous insulin administration for autopsy specimens. The document provides background on insulin structure and function, and exogenous insulin and insulin analogues. The four research objectives for the study were: to develop a quantitative multiple reaction monitoring (MRM) method on a triple quadrupole mass spectrometer; to develop an automated method that can be used to extract insulin and C-peptide from postmortem blood and vitreous humor; to validate the developed method according to Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines; and to perform a population assessment, in which paired postmortem blood and vitreous humor samples are collected and tested to establish therapeutic and overdose concentrations, and acetone and beta-hydroxybutyrate testing are preformed on the same blood and vitreous humor samples and glucose testing is performed on vitreous fluid samples. The report describes the authors’ research designs, methods, and analytical and data analysis. Outcomes include the development of a quantitative MRM method on a triple quadrupole mass spectrometer, and the development and validation of a comprehensive analytical workflow to determine exogenous analyte concentrations in vitreous fluid; the partial completion of the second project goal; and the method validation according to SWGTOX guidelines was also completed.