B-300 Fentanyl and Xylazine Positivity Patterns at a Northeast U.S. Children’s Hospital

Abstract

Abstract Background In the U.S., fentanyl mixed with xylazine has been designated as an emerging health threat. Information on whether xylazine is present with fentanyl poisoning could help better navigate the management of children exposed to fentanyl mixed with xylazine. The detection of xylazine can be a marker used to differentiate medical vs non-medical fentanyl exposure. We aimed to explore the trends in positivity rates of fentanyl and/or xylazine at an urban pediatric tertiary care hospital. Methods We conducted a retrospective analysis from October 2021 - January 2024 of fentanyl positive urine drug screen (UDS) results by immunoassay performed in-house, and the reflex confirmatory testing by liquid chromatography-tandem mass spectrometry (LC-MS/MS), performed by an external laboratory. When available, xylazine detection results by gas chromatography mass spectrometry (GC-MS) were also included in the analysis. A chart review of fentanyl positive UDS cases was conducted to determine if fentanyl was medically administered prior to the UDS. We evaluated the positivity rate of fentanyl, the co-detection of xylazine, and the positivity patterns based on age, sex, and collection department. Results Fentanyl positive tests encompassed 3.4% (227/6632) of all UDS performed at our institution and 11.0% (227/2058) of all positive UDS tests, with medical fentanyl administration prior to UDS documented in 76.2% (173/227) of cases. 217/227 samples had confirmatory testing with 96.8% (210/217) confirmed by LC-MS/MS. The median age of fentanyl positives was 7 years (41.9% ≤ 3 years old) and 57.3% were male. Fentanyl-only positive UDS were seen in 33.0% (75/227) of all fentanyl positives and 45.6% (108/227) were also positive for benzodiazepines. 68.7% (156/227) were collected in the intensive care units, and 19.8% (45/227) were from the emergency department. 46.7% (106/227) of fentanyl positive cases had concurrent GC-MS results available. Xylazine was detected in 13.2% (14/106) of these cases, with 13 cases reported as unintentional exposure on patients' chart, and 12 cases having a fentanyl-only positive UDS. The median age of xylazine positives was 2 years (71.4% ≤ 3 years old, age ranged from 19 days to 14 years) and 78.6% were male. 7/14 fentanyl mixed with xylazine cases were collected in the emergency department and 7/14 were collected in intensive care. 2/14 of the xylazine positive cases had medical fentanyl administration prior to UDS. Conclusions Detection and management of fentanyl poisoning, especially when mixed with xylazine, remains a challenge in children. Presence of xylazine is a distinct marker of exposure to non-medical fentanyl. Continued surveillance of these cases could shed light on patterns that could aid further the management of affected children and contribute to harm reduction efforts.