Journal Of Analytical Toxicology[JOURNAL]
Sun
200 papers
Prevalence of p-fluorofentanyl and xylazine in postmortem fentanyl casework.
Ballotari M, Truver MT, Hoyer JL … +2 more , Goldberger BA, Chronister CW
J Anal Toxicol · 2026 Jun · PMID 42234862 · Publisher ↗
In the United States (U.S.), fentanyl remains the leading drug associated with opioid-related deaths. Many analogs of fentanyl have been identified and linked to the opioid overdose epidemic. After core-structure schedul...
In the United States (U.S.), fentanyl remains the leading drug associated with opioid-related deaths. Many analogs of fentanyl have been identified and linked to the opioid overdose epidemic. After core-structure scheduling of illicitly manufactured fentanyl (IMF) and related products, para-fluorofentanyl (p-FF) reemerged with varied prevalence in the U.S. Xylazine also emerged as a cutting agent in IMF. The aim of this study was to describe the prevalence and trend use patterns of fentanyl, p-FF, and xylazine in a case series from 2021 to 2023 in the state of Florida. A three-year retrospective analysis of data was conducted. A total of 8121 cases were submitted for analysis over the period of study. Among them, 1530 cases (18.8%) tested positive for fentanyl in one or more of the specimens submitted for these cases. The age of the decedents ranged 16-85 years, with the majority being White males. The concentration range of fentanyl in the blood specimens (n = 1358) analyzed was 2.5-579 ng/mL. p-FF was detected with fentanyl in 164 postmortem blood specimens with a concentration range of 2.5-65 ng/mL. Xylazine was identified in the urine of 391 decedents. The combination of fentanyl, p-FF, and xylazine was detected in 70 cases. When fentanyl co-occurred with both xylazine and p-FF, it was primarily observed with benzodiazepines, cocaine, methamphetamine, and other opioids. This study aimed to provide a better understanding of the fentanyl analog and adulterant prevalence in Florida.
The identification of N-isopropyl butylone in postmortem cases in Northern Virginia.
Pluer A, Cooman T, Kessler M
J Anal Toxicol · 2026 Jun · PMID 42234859 · Publisher ↗
The emergence of synthetic cathinones in the illicit drug market over the past two decades has posed significant challenges for forensic laboratories. Marketed initially as "legal highs," these stimulants rose in popular...
The emergence of synthetic cathinones in the illicit drug market over the past two decades has posed significant challenges for forensic laboratories. Marketed initially as "legal highs," these stimulants rose in popularity around 2009, prompting the United States government to pass the Synthetic Drug Abuse Prevention Act in 2012. Despite regulatory measures, novel cathinones continue to surface in forensic casework. One such compound is N-isopropyl butylone, a structural isomer of N, N-dimethylpentylone-the most frequently identified synthetic cathinone in 2023 in the United States. Detected by the Virginia Department of Forensic Science in March 2024, N-isopropyl butylone has since appeared in items including solid material, powders, tablets, crystalline material, and residues in 170 Controlled Substances cases across the Commonwealth through July 2025. From July to September 2024, the Northern Laboratory's Toxicology Section presumptively identified the compound in six postmortem blood specimens with detection in an additional blood specimen in August 2025. This study investigates the seven toxicology cases, with three being selected for further research analysis. Cases were assessed for case history, additional toxicology findings, and cause/manner of death. Presumptive positive identifications were made using full-scan gas chromatography-mass spectrometry. Confirmation and semi-quantitative analysis utilized an adapted stimulant-targeted extraction with liquid chromatography-tandem mass spectrometry. N-Isopropyl butylone was confirmed in three cases at semi-quantitative values of 20, 200, and 1700 ng/mL. All seven cases involved poly-drug use with four deaths being attributed to drug intoxication and three to fatal gunshot wounds. Although N-isopropyl butylone has only been observed in seven postmortem Toxicology cases, its increased prevalence in Controlled Substances cases could indicate broader circulation. These findings highlight the growing concern over novel psychoactive substances and the need for continued surveillance and research to assess their role in forensic casework.
In response to letter to editor JAT-26-4812-Interpretation of breath cannabinoids and implications for impairment.
Deeb S, Fabian ZE, Määttä M … +2 more , Fraccarolli P, Engelhart DA
J Anal Toxicol · 2026 Jun · PMID 42233313 · Publisher ↗
Abstract loading — click title to view on PubMed.
In vitro metabolic profile characterization for synthetic cannabinoids MDMB-BINACA, MDMB-PICA, and AB-CHMINACA.
Eccarius LK, Stang BN, Walton SE … +2 more , Krotulski AJ, Logan BK
J Anal Toxicol · 2026 Jun · PMID 42226022 · Publisher ↗
The illicit synthetic cannabinoid receptor agonist (SCRA) market has experienced multiple changes since its appearance in the 2010s and, most recently, in response to a class-wide SCRA ban imposed by China in 2021. The r...
The illicit synthetic cannabinoid receptor agonist (SCRA) market has experienced multiple changes since its appearance in the 2010s and, most recently, in response to a class-wide SCRA ban imposed by China in 2021. The reemergence of "older" SCRAs, such as the highly potent indole- and indazole-3-carboxamide-containing drugs, has occurred due to the sale of unregulated precursors on grey-market and dark websites. This shift poses a significant threat to public health, and recent intoxication outbreaks associated with these types of SCRAs demonstrate the need for further toxicological research to aid in better understanding their metabolism and appropriate targets for toxicological testing. Testing for metabolites can extend the detection window of SCRAs as parent drugs are rapidly metabolized and present at low or potentially undetectable concentrations in biological samples, including urine. In these instances, metabolites may be more sensitive biomarkers of SCRA use. This study characterized the metabolites for the synthetic cannabinoids MDMB-BINACA (also known as MDMB-BUTINACA), MDMB-PICA, and AB-CHMINACA via in vitro human liver microsome (HLM) incubation and analysis by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Biotransformations observed in this study included ester and amide hydrolysis, oxidation, carboxylation, and dealkylation. Nine metabolites were identified for MDMB-BINACA, five of which were verified through retrospective analysis of authentic samples. Nine metabolites were also identified for both MDMB-PICA and AB-CHMINACA, with two metabolites of AB-CHMINACA verified in authentic samples. Characterization of the metabolism of these potent drugs allows for the use of the identified biomarker to improve forensic toxicology analyses and interpretation, especially when the use of synthetic cannabinoids is suspected.
Comprehensive toxicological characterization and quantitation of drugs identified among nonfatal opioid and stimulant overdose presentations to US emergency departments.
Stang BN, Kent JT, Walton SE … +8 more , Aldy K, Culbreth R, Falise A, Campleman S, Logan BK, Brent J, Wax P, Krotulski AJ
J Anal Toxicol · 2026 Jun · PMID 42226014 · Publisher ↗
Drug overdoses presenting to emergency departments (EDs) remain poorly characterized largely due to limitations resulting from constraints of hospital toxicology testing. This presents significant challenges for forensic...
Drug overdoses presenting to emergency departments (EDs) remain poorly characterized largely due to limitations resulting from constraints of hospital toxicology testing. This presents significant challenges for forensic and public health communities, as this population of primarily nonfatal overdoses is frequently not included with other data streams (e.g. fatalities, recreational drug markets), producing incomplete national and regional knowledge. To combat this issue, we performed a comprehensive toxicological analysis on patients presenting to EDs with suspected opioid or stimulant overdose. The Toxicology Investigators Consortium (ToxIC) implemented the Drug Toxico-Surveillance Reporting System at 17 healthcare institutions across the United States between April 2023 and September 2024, 995 patients (mortality rate = 1.0%, n = 10) were enrolled, and blood specimens were collected and analyzed at the Center for Forensic Science Research and Education. All specimens underwent blood alcohol analysis, comprehensive screening of over 1,200 xenobiotics, and quantitation for drugs of interest. At least one xenobiotic was detected in 992 specimens. Most frequently observed drugs include fentanyl (n = 713, mean: 8.0 ± 11 ng/mL), methamphetamine (n = 380, mean: 170 ± 210 ng/mL), and cocaine (n = 306, mean: 7.6 ± 15 ng/mL). There were 629 detections of 43 unique novel psychoactive substances (NPS), including potent alpha-2-agonists xylazine (n = 249, mean: 14 ± 29 ng/mL) and medetomidine (n = 31, mean: 1.5 ± 1.8 ng/mL). Regional trends observed include increased prevalence of methamphetamine in the western and central United States, alpha-2-agonists in the eastern United States, and greater NPS diversity in the eastern United States. Traditional opioids and stimulants were generally detected at higher mean concentrations than their more potent NPS counterparts. Quantitative data varies in comparison to literature on postmortem and driving under the influence of drugs cases. This is the first study to analyze blood specimens and provide quantitative data from a large sample of primarily nonfatal opioid/stimulant related overdoses.
Determination of nitazenes in postmortem casework and their prevalence in the State of Maryland.
Fagiola M, Phipps R
J Anal Toxicol · 2026 Jun · PMID 42216247 · Publisher ↗
The 2-benzylbenzimidazole class of synthetic opioids-more commonly referred to as the "nitazenes"-are the latest of several classes of novel psychoactive substances to predominate the illicit drug market. Following the c...
The 2-benzylbenzimidazole class of synthetic opioids-more commonly referred to as the "nitazenes"-are the latest of several classes of novel psychoactive substances to predominate the illicit drug market. Following the class-wide scheduling of fentanyl analogs and fentanyl-related substances in 2018, forensic toxicology laboratories in the United States began to see a proliferation of these novel synthetic opioids in casework initially stemming from the emergence of isotonitazene in 2019. Nitazenes are structurally distinct from fentanyl but share similar pharmacologic and toxicologic activity as mu-opioid receptor agonists with varying degrees of potency. In this study, we report the emergence and subsequent prevalence of the nitazenes in postmortem casework in the State of Maryland between May 2024 and August 2025. Analysis was completed utilizing a mixed-mode cationic exchange solid-phase extraction protocol and detection by ultra-performance liquid chromatography-triple quadrupole mass spectrometry. Four hundred and thirty postmortem cases were analyzed, with 3% of cases positive for one or more nitazenes. The most prevalent nitazenes detected were metonitazene (62% of positive cases), N-desethyl protonitazene (31% of positive cases), and N-pyrrolidino protonitazene (31% of positive cases). Only one case involved nitazenes as the sole substance of toxicologic significance; in all other cases, they were never the only drug detected and were frequently co-detected alongside fentanyl (85% of cases), followed by quinine (77% of cases), despropionyl fentanyl (69% of cases), cocaine/benzoylecgonine (62% of cases), and para-fluorofentanyl (54% of cases). Given the ever-changing landscape of novel psychoactive substances, the potency and increasing prevalence of these synthetic opioids raise significant concerns and underscore the need for ongoing surveillance, advancements in analytical techniques, and targeted public health interventions to mitigate their impact on mortality trends.
Postmortem redistribution and quantitative analysis of bromazolam, etizolam, flualprazolam, and flubromazolam.
Shoff EN, Kahl JH, Moore DM
J Anal Toxicol · 2026 Jun · PMID 42216246 · Publisher ↗
Novel Psychoactive Substances (NPS) have been consistently prevalent in postmortem casework at the Miami-Dade County Medical Examiner (MDME) for over a decade. Between May 2019 and September 2025, 88 positive identificat...
Novel Psychoactive Substances (NPS) have been consistently prevalent in postmortem casework at the Miami-Dade County Medical Examiner (MDME) for over a decade. Between May 2019 and September 2025, 88 positive identifications of NPS benzodiazepines were reported, including bromazolam (n=47), etizolam (n=25), flualprazolam (n=15), and flubromazolam (n=1). To improve interpretation of these findings, a quantitative method for these four analytes was developed and fully validated for postmortem blood and tissues utilizing solid phase extraction followed by ultra-high performance liquid chromatography-tandem mass spectrometry. Postmortem redistribution (PMR) was also evaluated for each analyte. In total, 180 specimens from 81 cases were analyzed, including 70 peripheral bloods, 72 central bloods, 18 liver homogenates, 16 brain homogenates, and 4 antemortem bloods. Peripheral blood concentrations for bromazolam (n=26) and etizolam (n=14) ranged from 2.5-168 ng/mL (mean: 33.4 ng/mL; median: 16.9 ng/mL), and 2.3-350 ng/mL (mean: 59.4 ng/mL; median: 12.1 ng/mL), respectively. Central blood concentrations for bromazolam (n=27) and etizolam (n=15) ranged from 3.0-153 ng/mL (mean: 38.3 ng/mL; median: 17.6 ng/mL), and 2.0-295 ng/mL (mean: 67.5 ng/mL; median: 15.3 ng/mL), respectively. Flualprazolam concentrations were notably lower with peripheral blood (n=3) concentrations ranging from 2.2-9.0 ng/mL (mean: 5.6 ng/mL; median: 5.7 ng/mL), and central blood (n=5) concentrations ranging from 2.4-10.6 ng/mL (mean: 6.0 ng/mL; median: 6.5 ng/mL). PMR ratios were calculated for central to peripheral blood (C/P), liver to peripheral blood (L/P), liver to central blood (L/C) and postmortem to antemortem blood (PM/AM). Median C/P and PM/AM ratios were ≤1.3, while median L/P ratios were ≤5.2. The observed PMR ratios are comparable to those reported for traditional benzodiazepines, suggesting limited PMR. The observed C/P ratios further suggest that central blood may be suitable for quantitative interpretation when peripheral blood is unavailable. This study represents the first systematic evaluation of C/P, L/P, L/C, and PM/AM ratios for NPS benzodiazepines across multiple cases.
Blood pharmacokinetics and use of metabolite-to-parent ratios to predict time of last zopiclone intake.
Gomonit MM, Nilsson GH, Nyström I … +6 more , Berglund L, Kugelberg FC, Chermá MD, Ahlner J, Truver MT, Kronstrand R
J Anal Toxicol · 2026 Jun · PMID 42216245 · Publisher ↗
Zopiclone (ZOP) is a sedative-hypnotic drug that is featured commonly in impaired driving, drug-facilitated crimes, accidental overdose, or suicidal intoxications. Further understanding of its blood pharmacokinetics woul...
Zopiclone (ZOP) is a sedative-hypnotic drug that is featured commonly in impaired driving, drug-facilitated crimes, accidental overdose, or suicidal intoxications. Further understanding of its blood pharmacokinetics would support its interpretation in forensic toxicology casework. This study characterizes the concentration-time pharmacokinetic profiles of ZOP and its metabolite N-desmethylzopiclone (N-DMZOP) in blood following controlled administration and evaluates the use of metabolite-to-parent ratios in estimating time of last ZOP intake. Sixteen subjects received a single oral dose of either 5 mg or 10 mg Imovane®, and blood samples were collected pre-dosing, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 24, and 48 hours post-dose. A paired plasma sample was also provided at the 2-hour time point. A previously validated LC-MS/MS method was used to quantify ZOP, N-DMZOP, and the degradation product 2-amino-5-chloropyridine (ACP). The aggregate regression model developed from this younger subject population was applied to independently dosed subjects and a separate group of elderly patients to determine the validity of this model in an older cohort of differing pharmacokinetic characteristics. Comparison between the 5 mg and 10 mg dosing groups supported a linear dose-concentration relationship. While the ratio of N-DMZOP/ZOP can be a predictive indicator for time of ZOP intake, inter-individual differences in ZOP disposition may influence such predictions. Furthermore, age-related pharmacokinetic changes may contribute to a general underestimation of predicted time with the current model, but a larger sample size of a broader demographic spectrum and dosing regimen would help improve the general applicability of this ratio-based modeling. Finally, we show that the mean blood-to-plasma ratio for ZOP and N-DMZOP were 0.79 and 0.92, respectively, suggesting a preferential partitioning of ZOP into the plasma fraction, which would be a useful reference when interpreting plasma concentrations from clinical studies against the more routinely sampled whole blood concentrations found in forensic toxicological casework.
Studies on enzymatic hydrolysis of psilocin-O-glucuronide for screening of psilocin in human urine by liquid chromatography-triple quadrupole tandem mass spectrometry.
Barajas DA, Carter HCN, Tomedi MR … +5 more , Lam HY, Deloatch TN, Reynolds GD, Castaneto MS, Ke P
J Anal Toxicol · 2026 Jun · PMID 42203689 · Publisher ↗
Psilocin is a psychedelic indole alkaloid and one of the major human metabolites of its phosphorylated precursor, psilocybin. Psilocin binds to the serotonin receptor, 5-HT2A, and dose-dependently induces hallucinogenic...
Psilocin is a psychedelic indole alkaloid and one of the major human metabolites of its phosphorylated precursor, psilocybin. Psilocin binds to the serotonin receptor, 5-HT2A, and dose-dependently induces hallucinogenic effects stronger than psilocybin. As a result, psilocin has been a drug of interest in the analytical toxicology community for years. In vivo, a majority of psilocin is metabolized to and excreted in urine as psilocin-O-glucuronide. Therefore, efficient conversion of psilocin-O-glucuronide to free psilocin directly impacts urine psilocin testing. Due to the chemical lability and light sensitivity of psilocin, the hydrolysis of psilocin-O-glucuronide requires relatively mild and carefully controlled reaction conditions, thus posing a significant challenge to analysts. In recent years, the development of recombinant β-glucuronidases offered a new approach for highly efficient deconjugation. However, to the best of our knowledge, little information on enzymatic hydrolysis of psilocin-O-glucuronide has been published since 2014. We utilized a certified LC-MS/MS-based psilocin screening method and investigated hydrolysis of psilocin-O-glucuronide in human urine catalyzed by one conventional β-glucuronidase (originating from E. coli) and three recombinant enzymes (IMCSZyme, Kura Biotech-BGTurbo, and Kura Biotech-B-One). The scope of our study included effects of enzyme concentration, pH, incubation time, and incubation temperature on the hydrolysis efficiency, as well as the comparison of modern enzymatic to traditional Brønsted-Lowry acidic and basic hydrolysis methods. The recombinant β-glucuronidases demonstrated remarkable superiority in hydrolysis efficiency compared to the E. coli-originated conventional β-glucuronidase. Kura Biotech-BGTurbo achieved the fastest hydrolysis completion at the lower temperatures (25-50°C) while IMCSZyme offered the most consistent performance across a wide range of incubation temperatures (25-80°C). Our findings provide quantifiable scientific references as a general guideline for other forensic toxicology laboratories to establish or optimize their own psilocin-O-glucuronide hydrolysis methods.
Correction to: The detection of cannabinoids in breath after ingestion of cannabis-infused edibles.
J Anal Toxicol · 2026 May · PMID 42186321 · Full text
Abstract loading — click title to view on PubMed.
A retrospective review of phencyclidine in hair samples of subjects from the United States workplace drug testing population.
Stowe GN, Loni E, Gonzalez A … +4 more , Furukawa R, Paulsen RB, Schaffer MI, Pietruszka M
J Anal Toxicol · 2026 Jun · PMID 42152229 · Publisher ↗
The dissociative anesthetic phencyclidine (PCP) remains an encountered analyte in typical routine testing in forensic toxicology. Herein, we describe a validated GC/MS method for PCP measurement in subjects using human h...
The dissociative anesthetic phencyclidine (PCP) remains an encountered analyte in typical routine testing in forensic toxicology. Herein, we describe a validated GC/MS method for PCP measurement in subjects using human head and body hair with a limit of detection (LOD) of 100 pg PCP/mg hair, with method linearity established from 100 to 15 000 pg PCP/mg hair. The GC/MS method was used to analyze samples from the USA workplace drug testing population (n = 368 samples) containing PCP over the years 2021 to 2025. The statistical comparison of PCP median concentrations for samples reported as black or brown in color or samples collected using head or body hair found no significant median concentration difference in either case. Many of the samples (65%) had the concurrent presence of at least one additional drug other than PCP, with cocaine (50%), amphetamines (20%), and cannabinoids (18%) as the most commonly observed drug substances. With the exception of an increased median concentration in year 2021, annual PCP median hair concentrations over the time period of this manuscript were stable.
Comment on Deeb et al.: interpretation of breath cannabinoids and implications for impairment.
Olson A
J Anal Toxicol · 2026 Jun · PMID 42090454 · Full text
This letter addresses the article by Deeb et al. describing the analysis of cannabinoids in exhaled breath. While the study represents a technical advancement in breath-based detection, several interpretive and analytica...
This letter addresses the article by Deeb et al. describing the analysis of cannabinoids in exhaled breath. While the study represents a technical advancement in breath-based detection, several interpretive and analytical limitations warrant clarification. The manuscript discusses potential impairment-related applications despite the absence of direct measures of impairment. Existing literature, including controlled clinical studies and government reports, indicates that THC concentrations in biological matrices cannot be used as a reliable indicator of impairment. Additionally, key variables influencing cannabinoid exposure, including dose, potency, and inhalation behavior, were not controlled, further limiting interpretability. Analytical concerns are also noted, including subpar chromatographic resolution (Rs ≈ 0.9), which may compromise accurate identification and quantitation of structurally similar cannabinoids. These issues highlight the need for caution in interpreting breath cannabinoid data, particularly in forensic contexts where conclusions regarding impairment may carry significant consequences.
N-pyrrolidino isotonitazene and its metabolites in post-mortem casework.
Wood R, Moore R
J Anal Toxicol · 2026 Jun · PMID 42046253 · Publisher ↗
N-pyrrolidino isotonitazene (Isotonitazepyne) is an extremely potent novel synthetic opioid which has been detected internationally in counterfeit pharmaceutical tablets. Published data from post-mortem cases is extremel...
N-pyrrolidino isotonitazene (Isotonitazepyne) is an extremely potent novel synthetic opioid which has been detected internationally in counterfeit pharmaceutical tablets. Published data from post-mortem cases is extremely limited and no metabolite profiles from authentic case work have been published. This paper describes a number of post-mortem cases in which N-pyrrolidino isotonitazene was thought to play a significant role in the cause of death, as well as describing the detected metabolite profiles. Concentration ranges for N-pyrrolidino isotonitazene was reported to be 1.1-55.9 µg/L across the 4 cases. The presumptive metabolite 5-amino-N-pyrrolidino isotonitazene was also identified in all samples; n-pyrrolidino-4-hydroxy nitazene was present in 3 of the 4 urine samples; and N-pyrrolidino hydroxy isotonitazene was present in 1 sample. This study highlights some of the challenges associated with nitazene interpretation, such as the very wide concentration ranges encountered in potentially fatal cases, as well as providing provisional metabolite data which may aid in detecting future cases.
An enduring threat: NPS benzodiazepines in forensic and clinical toxicology from 2021 to 2025.
Ellefsen KN, Karschner EL, Mérette SAM … +6 more , Patton AL, Shoff EN, Smith CR, Truver MT, Mata DC, Papsun DM
J Anal Toxicol · 2026 Jun · PMID 42033028 · Publisher ↗
The proliferation and sustained detection of novel psychoactive benzodiazepines in forensic and clinical toxicology, combined with their potential for adverse events, poses an enduring threat to public health and safety...
The proliferation and sustained detection of novel psychoactive benzodiazepines in forensic and clinical toxicology, combined with their potential for adverse events, poses an enduring threat to public health and safety with complex characteristics and challenges unique from other subclasses of novel psychoactive substances (NPS). This study aimed to systematically review the published effects, observations, and toxicological data from postmortem and human performance studies [including clinical, driving under the influence of drugs (DUID), and drug-facilitated crimes (DFC)] involving NPS benzodiazepines from 2021 to 2025. The challenges this class of compounds presents to clinicians, toxicologists, and medical professionals were also addressed, including both analytical and interpretative challenges. Literature reviews were performed in PubMed, Google Scholar, Google Search, toxicology journals, and conference abstract proceedings using search terms such as "NPS benzodiazepines," "designer benzodiazepines," and compound specific searches; authoritative websites such as NPS Discovery, National Forensic Laboratory Information System, and the European Union Drug Agency were also consulted. A total of 259 NPS benzodiazepine-related studies were identified including 29 postmortem, 15 DUID, 27 clinical, and 5 DFC studies detailed in this review. NPS benzodiazepines were widely pervasive in both postmortem and human performance cases with overlapping toxic and recreational concentrations; often involving polysubstance use with other central nervous system depressants and stimulants. Unique clinical presentations, observed effects, and autopsy findings were also reported for NPS benzodiazepines. This review provides an updated, consolidated resource to support toxicologists and clinicians in interpretation, emerging risk assessment, and evolving challenges associated with NPS benzodiazepines across postmortem and human performance settings.
Evaluating the impact of fentanyl immunoassay cutoff concentrations in emergency department, maternal, and neonatal populations.
Harsha ML, Weaver K, Clarke WA … +1 more , Rackow AR
J Anal Toxicol · 2026 May · PMID 42001212 · Publisher ↗
Qualitative urine drug screens (UDSs) are essential in clinical toxicology for assessments of drug exposure and are commonly employed by emergency departments to provide rapid results that inform care. Fentanyl, a potent...
Qualitative urine drug screens (UDSs) are essential in clinical toxicology for assessments of drug exposure and are commonly employed by emergency departments to provide rapid results that inform care. Fentanyl, a potent synthetic opioid, is of significant public health concern due to rising overdose rates. However, fentanyl is also administered clinically as an analgesic, which may result in positive UDS assessments for patients with iatrogenic exposure. Positive UDS findings may cause patient anxiety, provider confusion, and lead to medicolegal concerns in clinical settings such as labor and delivery and neonatology. As such, it is essential that UDSs are utilized appropriately and that the positivity threshold for the assay is rigorously evaluated to serve the clinical need. This study examined UDS utilization within a quaternary care system over a 1-year period. A subset of remnant urine specimens from UDSs was further analyzed using high resolution mass spectrometry (HRMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to focus on the impact of fentanyl immunoassay cutoff concentrations in high-volume populations. At our institution, the adult emergency department (ED) had the highest number of specimens ordered (5901), while neonatal units had the least (727). Notably, fentanyl positivity rates were the highest in neonatal units at 34%. Quantitative analysis of remnant urine samples from the ED, labor and delivery (L&D), and neonatal units showed higher fentanyl concentrations in the ED, indicative of illicit use, and lower concentrations in L&D and neonates, consistent with analgesic administration. Raising the immunoassay cutoff from 1.0 to 5.0 ng/ml would convert iatrogenic positives to negatives while retaining illicit positives. These findings underscore the need to evaluate UDS cutoff values for improved clinical performance in different populations.
The detection of N-propionitrile orphine in a urine sample.
Wood R, Moore R, Iula D
J Anal Toxicol · 2026 May · PMID 41981744 · Publisher ↗
Abstract loading — click title to view on PubMed.
Comparative performance of methadone urine immunoassays based on real-world data reveals assay interference.
Pagaduan JV
J Anal Toxicol · 2026 May · PMID 41967080 · Publisher ↗
Urine drug screen (UDS) immunoassays remain essential tools in clinical toxicology due to their rapid turnaround time and operational efficiency. However, their susceptibility to cross-reactivity continues to pose challe...
Urine drug screen (UDS) immunoassays remain essential tools in clinical toxicology due to their rapid turnaround time and operational efficiency. However, their susceptibility to cross-reactivity continues to pose challenges, particularly in complex patient populations receiving multiple medications. Verification studies performed prior to assay implementation often rely on limited sample sets and may not fully capture real-world assay performance. Ongoing post-implementation monitoring, especially through comparison with confirmatory assays such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), is therefore critical for identifying unexpected assay behavior and maintaining analytical reliability. This study evaluated the real-world concordance of two methadone immunoassays-the Architect MULTIGENT Methadone assay and the Roche Methadone II (MDN2) assay-with an in-house LC-MS/MS method capable of detecting methadone and its primary metabolite, 2-ethylidene-1, 5-dimethyl-3, 3-diphenylpyrrolidine (EDDP), at a cutoff concentration of 100 ng/mL. A total of 6753 Architect and 6255 Roche methadone screening results were retrospectively reviewed. The Architect assay demonstrated a 2.8% positivity rate, with 94.8% of positive screens confirmed by LC-MS/MS, corresponding to a 5.2% false-positive rate. In contrast, the Roche assay produced a higher positivity rate of 3.6% but a substantially lower confirmation rate of 69.8%, yielding a 30.2% false-positive rate (χ2 = 106, P < .05). Medication review of Roche false-positive cases revealed frequent use of quetiapine and vortioxetine, consistent with previously reported cross-reactivity. Additional medications historically associated with methadone immunoassay interference were also identified. These findings highlight significant performance differences between two widely used methadone immunoassays and underscore the importance of continuous, data-driven post-implementation surveillance. Confirmatory testing data such as LC-MS/MS results, can reveal clinically meaningful assay limitations, support accurate interpretation of unexpected results, and ultimately improve the reliability of UDS testing in diverse patient populations.
Confirmatory gas chromatography-mass spectrometry drug testing in pediatric patients: a clinical case series highlighting false-positive results and child protection implications.
Fernández N, Quiroga PN
J Anal Toxicol · 2026 May · PMID 41942107 · Publisher ↗
Drug exposure in pediatric patients represents a major clinical and forensic challenge, particularly when initial urine drug screening relies on immunoassays with limited specificity. False-positive and false-negative re...
Drug exposure in pediatric patients represents a major clinical and forensic challenge, particularly when initial urine drug screening relies on immunoassays with limited specificity. False-positive and false-negative results may lead to inappropriate clinical decisions or delayed child protection interventions. We conducted a retrospective case series of 14 pediatric patients (0-5 years) with suspected drug exposure evaluated in a hospital emergency setting. Positive immunoassay urine drug screens were submitted for confirmatory analysis using gas chromatography-mass spectrometry (GC-MS) at a reference toxicology laboratory. GC-MS confirmation identified a wide range of illicit and prescription substances and metabolites, including benzoylecgonine, cocaine, ecgonine methyl ester, phenobarbital, para-hydroxy-phenobarbital, lorazepam, morphine, sertraline and its metabolites, hydroxymidazolam, MDMA, MDA, and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH). In several cases, GC-MS resolved discordant screening results by identifying immunoassay false positives caused by cross-reactivity or by detecting substances missed during initial screening. Confirmatory GC-MS testing directly influenced clinical management and supported child protection decisions in cases of suspected neglect, accidental ingestion, or environmental exposure. These findings reinforce the critical role of mass spectrometry-based confirmation in pediatric toxicology to ensure diagnostic accuracy and appropriate clinical and legal outcomes.
Universal LC-MS/MS screening for GHB: advancing routine detection in postmortem toxicology and accuracy of death investigations.
Rodda LN
J Anal Toxicol · 2026 May · PMID 41896190 · Publisher ↗
Gamma-hydroxybutyric acid (GHB) is an endogenous compound and central nervous system depressant with legitimate therapeutic applications but frequent illicit use. Historically, GHB has been excluded from routine systemat...
Gamma-hydroxybutyric acid (GHB) is an endogenous compound and central nervous system depressant with legitimate therapeutic applications but frequent illicit use. Historically, GHB has been excluded from routine systematic toxicology testing because its detection typically required targeted analysis, limiting testing to cases where GHB use was specifically suspected. In 2020, our office implemented a validated LC-MS/MS screening platform that enabled GHB to be analyzed efficiently and universally across all forensic case types, including postmortem death investigations. Between May 2020 and April 2025, 15 GHB-associated fatalities were identified, with 11 (73%) having no investigative suspicion of GHB use. Most decedents were male, White, with the cohort having a median age of 39 years. Twelve deaths (80%) were accidental, and three (20%) were suicides. Concentrations in both blood and urine were consistent with exogenous exposure across all cases, frequently in the context of polysubstance stimulant use. Integration of GHB testing into routine testing workflows revealed multiple previously unrecognized fatalities, demonstrating that universal inclusion of GHB enhances accuracy in death certification, operational efficiency, and the completeness of forensic toxicology surveillance.
Sample validity lessons learned from challenging cases and proposed biomarkers for synthetic urine detection.
Joubert S, Lynch C, Carter A
J Anal Toxicol · 2026 May · PMID 41896188 · Publisher ↗
Toxicology laboratories rely on a combination of on-site and laboratory based validity testing to detect dilution, adulteration, and substitution in urine samples collected for drugs of abuse testing. At Melbourne Pathol...
Toxicology laboratories rely on a combination of on-site and laboratory based validity testing to detect dilution, adulteration, and substitution in urine samples collected for drugs of abuse testing. At Melbourne Pathology, Sample Validity Testing (SVT) includes on-site checks such as temperature, creatinine, color, and supervised collection, as well as routine laboratory testing of all specimens for creatinine, pH, and oxidants. Additional validity testing is performed when a specimen is deemed suspicious, including osmolality and the biomarkers urea, uric acid, amylase, and γ-glutamyltransferase (GGT). We describe three cases in which SVT was critical in identifying inauthentic specimens, and one where SVT resulted in the inaccurate identification of an authentic case as inauthentic due to a medical condition. We also present the SVT results from seven synthetic urine (SU) samples detected in routine casework. Urea and uric acid proved somewhat successful at identifying SU, present in three of the SU samples. GGT and amylase proved the most effective at identifying SU, with none of the SU samples containing the enzymes. These biomarker assays were rapid, cost‑effective, and readily implemented using existing biochemistry workflows. Our findings highlight that no single validity measure is sufficient in isolation; instead, results should be interpreted collectively and on a case‑by‑case basis. As SU formulations continue to evolve, laboratories may benefit from adopting additional, non‑routine validity tests tailored to their operational capacity.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe