“…Due to their unknown origins, compositions, and lack of regulation, the use of these substances presents risks of harm, including toxicity, overdose, and death. , These risks may be exacerbated when a drug sample has an unknown quantity or is adulterated via the addition of other pharmaceutically active compounds to dilute, bulk up, or otherwise improve the appearance and/or apparent quality of the product. − Additional risk exacerbation occurs when a drug is mis-sold, e.g., counterfeited pharmaceuticals, , or when conventional illicit drugs, e.g., cocaine, MDMA, and ketamine, are adulterated with or substituted for structurally related analogues or novel psychoactive substances (NPS) such as synthetic cathinones, synthetic cannabinoids, or novel synthetic opioids such as fentanyl and its analogues . Due to their ever-increasing number and structural diversity (up to December 2020, 1047 NPS have been reported), the pharmacological properties of many NPS and their subsequent potential for adverse side effects are poorly understood. − Therefore, to provide effective public health and harm reduction interventions at large public events, there is a need for rapid qualitative and quantitative identification and characterization of the drug substances and combinations that are in use, including NPS that have not previously been reported or characterized. , Information regarding the presence and/or concentrations/amounts of these substances and assessment of their potential adverse effects can then be relayed to relevant stakeholders, such as first aid and medical personnel, peer-based harm reduction workers, and/or event patrons.…”