OBJECTIVE: To develop a toxicological screening analysis using gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) on postmortem dried blood spots (DBSs), and apply it to authentic cases. METHOD: Twenty-five µL of blood was deposited and dried on a paper card. Compounds of interest were desorbed, extracted and acetylated, then injected into the GC-HRMS. The limits of detection (LOD) and of identification (LOI) were determined for 22 of the compounds most frequently detected in postmortem blood samples in the laboratory in 2022.Stability on DBS was studied at 3 temperatures (-20°C, +4°C, and +20°C) over 15 days. The method was then applied to 102 postmortem blood samples. Results were compared to the two conventional screening methods implemented in the laboratory: LC-DAD/MS and GC-MS. RESULTS: Selectivity was demonstrated by analysis of 10 negative postmortem blood samples. All LODs were between <
10.0 ng/mL and 20.0 ng/mL. LOIs were within the therapeutic concentration range for each compound or at a value not leading to acute intoxication (narcotics). Overall, compounds remained stable over the 15 days at all test temperatures, except for midazolam and tramadol and its metabolites. Comparison of screenings of 102 postmortem samples resulted in 239 identifications, corresponding to 74 compounds, across 70 positive cases. In 32 cases, no compound was identified. Respectively 57% and 60% of the compounds were detected by LC-DAD/MS and GC-MS screenings, while DBS-GC-HRMS identified 81%. DISCUSSION-CONCLUSION: Application of the method to a hundred authentic cases demonstrated its ability to meet the constraints of low sample volume, sensitivity and ease of preservation for urgent cases or cases with limited blood availability.