Complete coverage of emerging drugs of concern requires current methodology and access to analytical reference standards. Diekhans et al. describe an LC-MS/MS method for the comprehensive screening of synthetic opioids and xylazine in blood and urine samples in forensic toxicological casework. These findings were made possible, in part, by the Fentanyl Analog Screening (FAS) Kit and FAS Kit Emergent Panels Versions 1, 2, 3, and 4. The FAS Kit and its expansion panels contain analog reference standard materials for 250 synthetic opioid compounds, supporting the development of this new LC-MS/MS method for the identification of novel synthetic opioids and the co-drug xylazine in forensic toxicological casework.  

Key Article Takeaways

• A comprehensive new LC-MS-MS method for the identification of fentanyl analogs, precursors and byproducts, and metabolites, as well as the co-drug xylazine is described.

• This analytical method could identify 202 distinct synthetic opioid targets and target-groups, offering the broadest coverage of any analytical method known to us. 

• The method offers enhanced separation of isomeric analytes, allowing for improved distinction of structurally related compounds. The limits of detection reported herein are improved or comparable with existing methods.

• Samples from 617 fatal accidental overdoses in San Francisco in 2022 were retrospectively analyzed using this method. The prevalence of fluorofentanyl, a previously unreported fentanyl analog, in these cases highlights the need for comprehensive screening of new and emerging synthetic opioids.

• This analytical method supports the selective and sensitive identification of unknown synthetic opioids in forensic toxicological casework.

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Corresponding author, Luke N. Rodda, Ph.D., who serves as the Chief Forensic Toxicologist and Director of Forensic Laboratory Division at the San Francisco Office of the Chief Medical Examiner and Assistant Adjunct Professor of Laboratory Medicine at the University of California, San Francisco, commented, "with hundreds of novel synthetic opioids potentially available in communities, the FAS Kits have provided a unique opportunity for laboratories to develop screening methods for the most potent drug category we encounter in forensic toxicology casework."  

He continued, "Our experience showed that after implementing a routine screening method for the sensitive detection of over 200 fentanyl analogs, we were immediately able to show the significant prevalence of fluorofentanyl in fatal overdoses – improving both the cause of death determination and information shared to policymakers for better public health interventions."

About FAS Kits

The FAS Kit and its expansion panels are part of the Traceable Opioid Material^® Kits (TOM Kits^®) product line, which was designed and developed by the CDC to support laboratory detection and identification of current and emerging opioids.

The FAS Kit and its expansion panels are available free-of-charge to qualified labs through Cayman.

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