Methamphetamine concentrations in blood and gastric contents in 20 forensic autopsy cases

[ABSTRACT] Methamphetamine is one of the most commonly abused drugs and cases of methamphetamine-related death are not uncommon. In forensic autopsy cases, it is important to identify how a detected drug was taken to confirm whether an illegal substance was self-administered or possibly administered unknowingly. The present study involved 20 forensic autopsy cases examined at Okayama University between 2012 and 2020 in which methamphetamine was detected. In each case, methamphetamine concentrations in blood and gastric contents, along with other factors such as age, postmortem interval, and cause of death, were investigated, and the ratio of the methamphetamine concentration in gastric contents to that in blood (GB ratio) was determined. No correlations were observed between the GB ratio and age, postmortem interval, methamphetamine concentrations in peripheral blood and gastric contents, volume of gastric contents, or total amount of methamphetamine in gastric contents. A good correlation was observed between methamphetamine concentrations in peripheral blood and in gastric contents. The maximum GB ratio was 58.8 in a case in which it was suspected that there had been prolonged general prostration before death. In cases without prolonged general prostration, the maximum GB ratio was 26.8, which was less than the value of 36 that was previously reported as the threshold for judging whether the methamphetamine detected was taken orally.