The distribution and redistribution of carfentanil in post mortem samples

This article compares 290 post mortem case reports that were positive for carfentanil. All the cases were submitted to, and analyzed by, the toxicology department of the Office of the Chief Medical Examiner, Edmonton, Alberta, Canada. This study highlights the varied distribution of carfentanil in the body after death as a result of misadventure, i.e., these are accidental drug overdose cases. Post mortem samples were collected from more than one anatomical site and analysed for carfentanil using a validated liquid chromatography-tandem mass spectrometry method. Ante-mortem samples were available in 15 of these cases and were also analysed. Post mortem mean blood carfentanil concentrations were found to be 0.362 μg/L (femoral), 0.442 μg/L (iliac), 0.484 μg/L (cardiac) and 0.692 μg/L (subclavian). The mean vitreous humor carfentanil concentration was 0.238 μg/L; the mean urine carfentanil concentration was found to be 0.697 μg/L. Little difference was found between ligated and 'blindstick' femoral blood carfentanil concentrations. Whilst carfentanil can readily be detected in both vitreous humor and urine samples neither were found to correlate with blood concentrations, limiting their use in interpretation. This study demonstrates the importance of multi-site sample collection and subsequent analysis for a thorough post mortem toxicological investigation. The study also highlights the risks and limitations associated with the interpretation of post mortem analytical results concerning carfentanil.