The illicit drug market is constantly evolving. New drugs (called novel psychoactive substances, or NPS) are steadily emerging, evading detection and legal consequences. Between January 2018 and December 2023, the Center for Forensic Science Research and Education’s NPS Discovery identified more than 250 NPS in forensic samples tested from the United States, totaling more than 15,000 detections across forensic populations nationally.”[1]
One way to better understand the evolving drug landscape is to analyze postmortem fluids and tissues. Forensic toxicology laboratories, at the request of a medical examiner or coroner office, routinely screen for prescription, illicit, and over-the-counter drugs. Unfortunately, many of these laboratories — which are often understaffed and underfunded — tend to have ever-growing backlogs.[2] Postmortem laboratories need cost-effective methods to quickly test for numerous drugs. Many use a test called an ELISA[3] to detect drugs of abuse. However, ELISA is not specific enough to detect many novel psychoactive substances, distinguish them from other common classes of controlled substances, or differentiate them from close analogues.
Dr. Diane Moore, a toxicologist for the Miami-Dade County Medical Examiner, sought a method to provide more detail about substances found in postmortem blood and tissues and a higher degree of confidence in their identification. With NIJ funding, her department purchased instrumentation to perform liquid chromatography tandem mass spectrometry (LC/MS/MS) to improve their workflow and augment their current screening procedure using gas chromatography-mass spectrometry (GC/MS).
Dr. Moore’s team developed a method for rapid, large-scale blood sample screening to augment current procedures and replace their traditional approach to toxicology testing. Optimally, they were seeking to develop operating procedures that would simultaneously scan for a wide range of drugs while still identifying and differentiating among closely related drugs. The team compared their results to current methods and created a searchable library that includes relevant drugs found in present-day toxicology screens.
According to Dr. Moore, “The method we developed . . . is reproducible, [the output is] library searchable, and has a high correlation with other testing methods. It reduces the possibility of false positives and negatives in our work. It is an improvement over current methods using LC/MS/MS as a tool for drug identification.”
An Internal Searchable Library for Drugs and Their Analogues
The researchers scanned postmortem fluids for a wide range of drug classes, including benzodiazepines, sympathomimetic amines (like ecstasy), cocaine and cocaine metabolites, fentanyl and fentanyl analogues, opiates and opioids, and cannabinoids. They validated the method according to recognized industry standards and created an internal searchable library of 60 frequently identified analytes that are currently detectable by ELISA screens. The researchers hope to expand the library in the future.
The team began implementing the new screening procedure in November 2022. Since then, they have performed approximately 2,200 tests in routine case work.
Practice Implications
The team found that the new technique has a high recovery across a range of compounds while improving sensitivity and specificity. They eliminated the old method for initial screening and found that the new method exceeds expectations, reducing the number of tests performed per case along with testing-related costs.
The new method also shortened overall testing turnaround time. According to Dr. Moore, “Prior to the implementation of this method, the laboratory’s average turnaround time was 45-50 days. Since we began utilizing this testing method the average turnaround time has decreased to under 40 days.” She acknowledged that the improved turnaround time could not solely be attributable to the testing method, however, and surmised that its contributions may be better understood over time.
Dr. Moore continued, “Our laboratory takes its obligation to community service very seriously. The information generated by our Medical Examiner department is essential not only in death investigations but also public safety and health. In toxicology this means identifying a much broader scope of toxic drugs and poisons in our community and be a source of data for those agencies involved in the treatment drug addiction and studying trends in the use of recreational drug use in our community.”
About This Article
The work described in this article was supported by NIJ award number 2019-DU-BX-0002, awarded to Miami-Dade County.
This article is based on the grantee report “Combining LC/MS/MS Product-Ion Scan Technology with GC-MS Analysis to Identify Drugs and Poisons in Postmortem Fluids and Tissues” (pdf, 39 pages), Diane M. Moore.