Blood biochemical markers could improve the reliability of postmortem alcohol analyses

Quantification of alcohol levels in postmortem blood after road-traffic crashes is of importance for the determination of the driver's state of inebriation at the time of death. However, in certain circumstances such results are difficult to interpret because of the necrokinetics phenomenon, which involves changes in drug concentration at different rates over time in different corpse sites, happening at early stage after death. The present study shows cases of alcohol-intoxicated men that died due to head or chest traumatic injuries in road-traffic crashes. Toxicological results showed differences according to sampling site in blood alcohol concentrations in addition to alterations in blood or serum parameters like hematocrit, water content, pH and cytosolic enzyme activity. It was found, as expected, a progressive impairment in cellular permeability and dehydration in central blood cells, although this was accompanied by a diminution in alcohol concentration. However, peripheral blood showed hematocrit, water content and cytosolic enzyme activity values similar to those observed in living persons. Such findings suggest that blood alcohol levels obtained from peripheral sites constitute a reliable indicator of the state of inebriation at the time of death and in the early postmortem stage, as long as blood or serum parameters do not exceed normal limits. We propose that blood samples used for alcohol determination must be obtained from peripheral sites and may be accompanied by a measure of a blood biochemical marker in order to provide reliability to toxicological findings and to minimize detrimental effects of decomposition processes in the early postmortem stage.