The Elephant in the Room: Outbreak of Carfentanil Deaths in Minnesota and the Importance of Multiagency Collaboration.

Over a three-month period in early 2017, the Hennepin County Medical Examiner's Office investigated nine apparent opioid toxicity deaths that occurred in three separate urban, suburban, and rural counties in our jurisdiction. All decedents were known substance abusers and had reportedly recently used heroin; most were found with drug paraphernalia. Complete autopsies variably showed classic stigmata of opioid overdose with no significant injury or natural disease to explain death. Initial toxicology screens failed to identify heroin or other narcotic substances. Several cases were presumptively positive for fentanyl by immunoassay, yet failed to confirm positive for fentanyl. Following American Board of Forensic Toxicology reporting standards, these cases were reported as negative for fentanyl by the laboratory. Due to the discrepant scene and toxicology findings suggestive of an opioid toxicity death, further discussion between the medical examiners and toxicologists prompted additional testing at a referral laboratory. This resulted in quantifiable blood carfentanil in all cases (mean 0.26 ng/mL, range 0.12 - 0.64 ng/mL). Cointoxicants included ethanol (n=2), methamphetamine (n=3), benzodiazepines (n=3), and cocaine (n=1). No case had definitive evidence of acute heroin intoxication, but two cases had low concentrations of morphine present (0.03 and 0.06 ng/mL), and two others had 6-monoacetyl morphine in the urine without morphine in the blood, suggesting recent use. All deaths were certified as accidental acute or mixed carfentanil toxicity. These cases present additional information about carfentanil-related deaths and highlight the importance of collaboration between forensic pathologists and toxicologists.