Use of blood micro-samples in forensic thanatology.

In forensic thanatology, post-mortem blood is often stored for long periods, leading to in vitro variations in drug concentrations. This study evaluated the use of dried blood microsampling supports dried (Dried Blood Spot - DBS and Volumetric Absorptive MicroSampling (VAMS) as an alternative to conventional tubes. 72 bodies were sampled, including 35 analyzed toxicologically. 6 categories of substances (26 molecules) were quantified using LC-MS/MS or LC-HRMS. Heroin, several benzodiazepines, and cocaine showed excellent stability on DBS, while they degraded or disappeared in conventional tubes. In some cases, the absence of a micro-sample would have prevented the diagnosis of intoxication. For other molecules, concentration differences between DBS and conventional tubes did not alter the medico-legal interpretation, with equivalent values for morphine, codeine, and tramadol. THC and its metabolites remained difficult to extract from DBS. Microsampling has improved the qualitative detection of unstable drugs in post-mortem blood in routine forensic thanalogic sampling practice.