Drug testing in the era of new psychoactive substances

Traditional clinical toxicology involves the analysis of patient urine samples by immunoassays designed to detect opiates/opioids, amphetamine/methamphetamine, benzodiazepines, barbiturates, cocaine metabolite and tetrahydrocannabinol. Expanded drug screens may also include assays for oxycodone, buprenorphine, methadone, 6-monoacetylmorphine, phencyclidine and fentanyl. Patient samples that are positive are commonly reflexed to be run on a liquid chromatography-tandem mass spectrometry confirmatory assay, as are samples that are negative for drugs that are prescribed to the patient. These mass spectrometry assays are targeted and so only detect the drugs or drug metabolites that they were designed to detect. With the explosion of new psychoactive substances in the past decade, it has become necessary for clinical laboratories to reevaluate traditional targeted drug screening approaches. The utility of high-resolution mass spectrometry in this arena has been recognized and this review will discuss the traditional approach to, and the recent advances in clinical toxicology including data collection and interrogation strategies for new psychoactive substances using high-resolution mass spectrometry (HRMS). Various modes of data processing techniques including targeted analysis, suspect screening and non-targeted analysis will also be described using HRMS. Several published methods will be described to demonstrate the utility of various data acquisition and processing techniques using HRMS in NPS analysis specifically.