In July of 2016, the animal tranquilizer, carfentanil (CF) emerged in Northeast Ohio as an abused substance resulting in over 25 deaths within a 30-day period alone. Over 160 deaths were reported to Summit County and Cuyahoga County Medical Examiners Offices relating to the presence of CF either alone, or in combinations with heroin and fentanyl. Prior to this increase in CF cases, positive fentanyl enzyme-linked immunosorbent assay (ELISA) screening results were increasing in number. Many of these cases were found to be negative for fentanyl confirmation by gas chromatography-mass spectrometry (GC-MS). Fentanyl analogs such as CF, acetyl fentanyl (AF), 2-furanyl fentanyl (2-Fu-F) and 3-methylfentanyl (3-MF) may be present in these cases. Some fentanyl analogs like CF and 3-MF do not cross-react with commercial ELISA fentanyl assay. With the emergence of potent synthetic fentanyl analogs, questions arose as to how to interpret their very low concentrations or absence in the blood in relation to cause of death.

In a new paper authored by Szabolcs Sofalvi et al., published in Journal of Analytical Toxicology ((2017) 41 473–483), a validated method involving extraction of CF and other fentanyl analogs using Clean Screen® DAU and LC-MS/MS was reviewed to answer these questions regarding fentanyl analog identification and their corresponding concentrations. The above noted method monitored fentanyl, norfentanyl (NF) and four analogs: AF, 2-Fu-F, 3-MF and CF and has been employed to quantify these above analogs in blood and vitreous humor in authentic antemortem and postmortem cases. Calibration curves were established between 0.10–4.0 ng/mL (NF, AF, 3-MF, 2-Fu-F and CF) and 1.0–40 ng/mL for fentanyl. In total, 98 postmortem cases analyzed by the procedure using Clean Screen® DAU extraction produced the following blood concentration ranges: CF (0.11–0.88 ng/mL), 3-MF (0.15–1.7 ng/mL), 2-Fu-F (0.15–0.30 ng/mL), AF (0.14–0.16 ng/mL), fentanyl (1.1–15 ng/mL) and NF (0.10–3.7 ng/mL). Only CF, fentanyl and NF were detected in a statistically significant subset DUID population of 26 cases, producing concentration ranges between 0.11 and 0.47 ng/mL, 1.0 and 9.8 ng/mL, and 0.11 and 3.5 ng/mL, respectively.

This article demonstrates the power and efficiency of Clean Screen® DAU in the extraction of novel fentanyl analogs when applied to complex matrices such as postmortem blood. For more information regarding Clean Screen® DAU visit