A postmortem skin-extract study reported approximately 95% average positive identification overlap with conventional toxicology for 19 selected drugs and metabolites. That is promising agreement, but it is not independently validated 95% sensitivity for all drugs, all deceased people or every collection condition. The investigators expressly lacked a definitive ground truth for calculating sensitivity and selectivity.
Who was studied and how was skin sampled?
Wasinger and colleagues studied 93 people undergoing medicolegal autopsy in Vienna over one year. They included 37 females and 56 males, aged 17–94 years. Exact time of death was unknown in 35 cases. In cases with known timing, the methods report a mean death-to-autopsy interval of 8.7 days and maximum of 18 days; the discussion uses a different average of 8.3 days, so the report does not support assigning one uniform interval to all cases.
Water-wetted paper was held against the fingers or sole for five minutes. The first 23 people had three collection sites, including a rinsed right hand and an unwashed left hand. Later cases generally had an unwashed hand and foot sampled. Samples were stored at −20°C for up to three months before extraction and analysis.
This was extraction from the postmortem skin surface, not active sweat production from a living person. It also was not a validated quantitative measurement of the amount of drug in the entire skin.
What was the comparator?
Routine forensic toxicology used a validated screening procedure covering more than 400 compounds in available blood, urine, gastric contents and tissues. Peripheral blood was femoral arterial blood. Other collections included venous sinus blood and brain; advanced autolysis sometimes required sampling mixed brain material rather than defined regions.
The research dermal method used untargeted high-resolution LC–MS/MS. Candidates were evaluated through exact mass, isotope patterns and fragmentation. Nine substances had additional authentic-standard retention-time verification. Identification evidence was therefore not identical for every reported compound.
The percentages depended on compound and comparison
Conventional toxicology identified 123 different compounds across the cohort; 82 were identified in dermal extracts. That 82/123 compound coverage is a separate measure from average positive overlap for the selected 19-drug comparison.
Average positive overlap was approximately 95%, while average negative overlap was approximately 87%. Results varied materially: fentanyl positive overlap was 69.2%, norfentanyl 50%, morphine 91.3% and ketamine 91.7%. Several other targets had 100% positive overlap, sometimes based on only one or two comparator-positive cases.
Equal marginal counts did not guarantee matching people. Fentanyl was reported in 13 people by each approach, yet positive overlap was only 69.2%. The two sets of 13 were not identical. Nor can one target’s 100% overlap in two cases establish high precision for its future performance.
Why disagreement did not identify a universal winner
Some dermal-positive findings lacked a conventional-positive counterpart. Possible explanations included contamination, different biological detection windows and differences in analytical scope. Conventional toxicology was useful as a comparator but did not independently establish the true exposure status for every discordant finding.
The authors acknowledged that the untargeted method had limited sensitivity and required further targeted-method development. Its favorable aggregate overlap should not be presented as complete confirmation or an established replacement for conventional forensic testing.
No blood concentration could be recovered from a skin signal
The dermal evaluation was qualitative. Collection lacked a standard specimen volume or weight for normalization, and quantitative signals varied substantially. The paper did not establish analyte-specific dermal calibration, validated concentration cutoffs for exposure or a conversion to blood concentration.
The method may help identify cases needing further investigation. It does not independently establish dose, impairment or cause of death. For related distinctions, see the scope of a negative autopsy drug screen and why accurate mass alone does not settle identity.
Primary source
Wasinger D, Stolz K, Wolf M, et al. Analysis of postmortem dermal extracts is an efficient illicit drug screening method supporting forensic medicine. Scientific Reports. 2026;16:14183. doi:10.1038/s41598-026-45056-5.
Leave a Reply