Detectability of fentanyl and designer fentanyls in urine by 3 commercial fentanyl immunoassays

Rapid and Sensitive Detection of Fentanyl and Its Analogs by a Novel Chemiluminescence Immunoassay

BACKGROUND

Abuse of fentanyl and its analogs is a major contributor to the opioid overdose epidemic in the United States, but detecting and quantifying trace amounts of such drugs remains a challenge without resorting to sophisticated mass spectrometry-based methods.

METHODS

A sensitive immunoassay with a sub-picogram limit of detection for fentanyl and a wide range of fentanyl analogs has been developed, using a novel high-affinity antibody fused with NanoLuc, a small-size luciferase that can emit strong and stable luminescence. When used with human urine samples, the assay has a sub-picogram limit of detection for fentanyl, with results fully concordant with LC-MS.

RESULTS

When applied to clinical samples, the novel chemiluminescence immunoassay can detect low positive fentanyl missed by routine screening immunoassays, with a limit of detection of 0.8 pg/mL in human urine. When applied to environmental samples, the assay can detect levels as low as 0.25 pg fentanyl per inch2 of environment surface. Assay turnaround time is less than 1 h, with inexpensive equipment and the potential for high-throughput automation or in-field screening.

CONCLUSIONS

We have established a novel assay that may have broad applications in clinical, environmental, occupational, and forensic scenarios for detection of trace amounts of fentanyl and its analogs.

Understand the FDA-cleared fentanyl testing: A clinical evaluation of the SEFRIA fentanyl immunoassay

BACKGROUND

Screening for fentanyl has been adopted by many clinical laboratories to detect illicit drug use and monitor medication adherence. However, compared to other urine drug testing, fentanyl screening assays are relatively new and therefore their clinical performances are largely unknown. This study extensively evaluated the clinical performance, positive cutoff, and interference profile of SEFRIA fentanyl immunoassay in real patient settings.

METHODS

The FDA-cleared cutoff of 1.0 was verified with 21 urine samples with low or undetectable levels of fentanyl. After assay implementation, all screened-positive samples were confirmed by liquid chromatography-tandem mass spectrometry. A new cutoff was derived from the numeric values of the false positive (FP) screening results. The FP rates before and after implementing the new cutoff were compared. Interferences were identified by an untargeted drug analysis and confirmed by spiking experiments.

RESULTS

A total of 3951 screening results were reviewed in the first two months of the assay utilization, 410 were screened-positive, and 157 (38 %) were FP. After a new cutoff of 1.3 was implemented, the FP rate was reduced to 17 % based on 11119 screening results. Trazodone, labetalol, and haloperidol were identified as major interferents, accounting for 56 % of the FP results using the cutoff of 1.3.

CONCLUSION

By applying the new cutoff and including an interference comment to positive screening results, the FP rate was reduced from initial 38 % to 7.5 % (17 % times 56 %).

A critical review of workplace drug testing methods for old and new psychoactive substances: Gaps, advances, and perspectives

Workplace drug testing (WDT) is essential to prevent drug abuse disorders among the workforce because it can impair work performance and safety. However, WDT is limited by many challenges, such as urine adulteration, specimen selection, and new psychoactive substances (NPS). This review examined the issues related to WDT. Various scientific databases were searched for articles on WDT for drug detection published between 1986 (when WDT started) and January 2024. The review discussed the history, importance, and challenges of WDT, such as time of specimen collection/testing, specimen adulteration, interference in drug testing, and detection of NPS. It evaluated the best methods to detect NPS in forensic laboratories. Moreover, it compared different techniques that can enhance WDT, such as immunoassays, targeted mass spectrometry, and nontargeted mass spectrometry. These techniques can be used to screen for known and unknown drugs and metabolites in biological samples. This review assessed the strengths and weaknesses of such techniques, such as their validation, identification, library search, and reference standards. Furthermore, this review contrasted the benefits and drawbacks of different specimens for WDT and discussed studies that have applied these techniques for WDT. WDT remains the best approach for preventing drug abuse in the workplace, despite the challenges posed by NPS and limitations of the screening methods. Nontargeted techniques using high-resolution liquid chromatography-mass spectrometry (MS)/gas chromatography-tandem MS can improve the detection and identification of drugs during WDT and provide useful information regarding the prevalence, trends, and toxicity of both traditional and NPS drugs. Finally, this review suggested that WDT can be improved by using a combination of techniques, multiple specimens, and online library searches in case of new NPS as well as by updating the methods and databases to include new NPS and metabolites as they emerge. To the best of the author's knowledge, this is the first review to address NPS as an issue in WDT and its application and propose the best methods to detect these substances in the workplace environment.

Performance of Fentanyl Immunoassays in an ED Patient Population

BACKGROUND

Fentanyl is a synthetic opioid fueling the current opioid crisis in the United States. While emergency department (ED) visits due to opioid-related overdoses, injection complications, and withdrawals become increasingly more frequent, fentanyl is not detected in routine toxicology testing. We evaluated 2 FDA-approved fentanyl immunoassays in a sampled ED population.

METHODS

De-identified, remnant urine specimens (n = 213) collected from patients presenting to a large ED were analyzed using ARK Fentanyl II (ARK II) and Immunalysis SEFRIA (SEFRIA) fentanyl immunoassays on an Architect c16000 (Abbott) analyzer. All discrepant specimens were evaluated by LC-MS/MS. Additionally, polysubstance abuse patterns and trends were analyzed.

RESULTS

While intra-assay imprecision was comparable for ARK II and SEFRIA, inter-assay imprecision for ARK II and SEFRIA varied from 8.0% to 1.8% and from 37% to 12.5%, respectively. SEFRIA had a marginally higher false-positivity rate (3%) than ARK II (1%). Both assays had equivalent sensitivity of 95%, with ARK II (99%) having greater specificity than SEFRIA (97%). Fentanyl was detected in 13.7% of drug-panel-positive patient samples and most frequently observed in patients also testing positive for amphetamines and cocaine. Notably, fentanyl was detected in 5.3% of patient samples that were negative for all other drugs in our standard toxicology panel.

CONCLUSIONS

A sizable portion of drug-positive samples from our ED were positive for fentanyl, with a subset of patients testing positive for fentanyl alone. Implementation of fentanyl testing into routine toxicology panels can elucidate polysubstance abuse paradigms and capture ED patients that would go undetected in standard panels.

Quantification of Fentanyl and Norfentanyl in Whole Blood Using Liquid Chromatography-Tandem Mass Spectrometry

Fentanyl is a synthetic opioid used in pain management with a potency 50-100 times that of morphine. Due to fentanyl's high potency, very low dosages are needed to elicit the desired response. Fentanyl is gaining popularity as a drug of abuse. Overdose of fentanyl causes respiratory depression that can lead to death. Fentanyl undergoes N-dealkylation in the liver to its inactive metabolite norfentanyl. Quantitation of fentanyl and its metabolite norfentanyl in whole blood can be performed using liquid chromatography-mass spectrometry. In this method, whole blood samples are spiked with deuterated internal standards for fentanyl and norfentanyl. The samples are alkalized with potassium hydroxide and the drugs are extracted with an organic solvent. Extracts are dried and reconstituted, then injected on LC-MS/MS. They are quantitated using positive ion multiple reaction monitoring (MRM) mode.

Software-assisted automated detection and identification of "unknown" fentanyl analogues

Fentanyl and its non-pharmaceutical analogues (NPFs) are potent synthetic opioids, traditionally used for pain management, with ever-increasing illicit uses. Tightening the regulation for known fentanyls leads to new synthetic analogues in the opioid market. Furthermore, the Organization for the Prohibition of Chemical Weapons (OPCW) has recently issued a decision regarding aerosolized use of central nervous system (CNS)-acting agents, such as fentanyl and its analogues, under the concern that these materials could be misused for terror or war purposes. The ever-increasing development of new fentanyl analogues makes the task of detection and identification of these new, unknown analogues crucial. In this work, we introduce an automated tool for the detection and putative identification of "unknown" fentanyl analogues, using liquid chromatography-mass spectrometry (LC-MS) (high-resolution mass spectrometry [HRMS]) analysis, subsequently followed by data processing using the "Compound Discoverer" software. This software, in our modified use, enabled the automatic detection of various fentanyl analogues, by "digging" out components and comparing them to pre-calculated theoretical molecular ions of possible modifications or transformations on the fentanyl backbone structure (no library or database used). Subsequently, structural elucidation for the proposed component of interest is carried out by automated MS/MS data interpretation, as performed by the software. This method was explored on 12 fentanyl-based "unknown" analogues used as model examples, including chemical modifications such as fluorination and methylation. In all tested compounds, automatic detection and identification were achieved, even at concentrations as low as 1 ng/mL in an environmental soil matrix extract.

Review of analytical methods for screening and quantification of fentanyl analogs and novel synthetic opioids in biological specimens

Fentanyl, fentanyl analogs, and other novel synthetic opioids (NSO), including nitazene analogs, prevail in forensic toxicology casework. Analytical methods for identifying these drugs in biological specimens need to be robust, sensitive, and specific. Isomers, new analogs, and slight differences in structural modifications necessitate the use of high-resolution mass spectrometry (HRMS), especially as a non-targeted screening method designed to detect newly emerging drugs. Traditional forensic toxicology workflows, such as immunoassay and gas chromatography mass spectrometry (GC-MS), are generally not sensitive enough for detection of NSOs due to observed low (sub-μg/L) concentrations. For this review, the authors tabulated, reviewed, and summarized analytical methods from 2010-2022 for screening and quantification of fentanyl analogs and other NSOs in biological specimens using a variety of different instruments and sample preparation approaches. Limits of detection or quantification for 105 methods were included and compared to published standards and guidelines for suggested scope and sensitivity in forensic toxicology casework. Methods were summarized by instrument for screening and quantitative methods for fentanyl analogs and for nitazenes and other NSO. Toxicological testing for fentanyl analogs and NSOs is increasingly and most commonly being conducted using a variety of liquid chromatography mass spectrometry (LC-MS)-based techniques. Most of the recent analytical methods reviewed exhibited limits of detection well below 1 μg/L to detect low concentrations of increasingly potent drugs. In addition, it was observed that most newly developed methods are now using smaller sample volumes which is achievable due to the sensitivity increase gained by new technology and new instrumentation.

Advances in fentanyl testing

Fentanyl is a synthetic opioid that was approved by the FDA in the late 1960s. In the decades since, non-prescription use of fentanyl, its analogs, and structurally unrelated novel synthetic opioids (NSO) has become a worsening public health crisis. There is a clear need for accessible testing for these substances in biological specimens and in apprehended drugs. Immunoassays for fentanyl in urine are available but their performance is restricted to facilities that hold moderate complexity laboratory licenses. Immunoassays for other matrices such as oral fluid (OF), blood, and meconium have been developed but are not widely available. Point of care tests (POCT), such as lateral flow immunoassays or fentanyl test strips (FTS), are widely available but not approved by the FDA for clinical use. All immunoassays are vulnerable to false positive and false negative results. Immunoassays may or may not be able to detect fentanyl analogs and NSOs. Mass spectrometry (MS) can accurately and reliably measure fentanyl and its major metabolite norfentanyl in urine and oral fluid. MS is available at reference laboratories and large hospitals. Liquid chromatography paired with tandem mass spectrometry (LC-MS/MS) is the most widely used method and has outstanding specificity and sensitivity for fentanyl and norfentanyl. When compared to immunoassays, MS is more expensive, requires more technical skill, and takes longer to result. Newer mass spectrometry methods can measure fentanyl analogs and NSO. Both mass spectrometry assays and immunoassays [in the form of fentanyl test strips (FTS)] have potential use in harm reduction programs.

New trends of new psychoactive substances (NPS)-infused chocolate: Identification and quantification of trace level of NPS in complex matrix by GC-MS and NMR

For the first time, the identification and quantification of trace level of new psychoactive substances (NPS) in a complex chocolate matrix have been reported. Since the beginning of 2022, suspected NPS-infused chocolate samples confiscated in inbound packages have been continuously sent to our laboratory for analysis. The qualitative gas chromatography-mass spectrometry (GC-MS) results were verified by ¹H nuclear magnetic resonance (¹H NMR) and ¹⁹F NMR to distinguish between potential aromatic isomers. A total of 11 NPS including deoxymethoxetamine, 3-OH-PCP, 6-APB, 4-APB, 4-OH-MiPT, 3-FEA, 2-FEA, 3-MMC, bromazolam, 2-FDCK, and ADB-BUTINACA were detected in 65 seized chocolate samples. A general ¹H quantitative NMR (¹H qNMR) method for quantification of 297 types of NPS in complex chocolate matrixes was devised for the first time after rigorous analysis of various critical features of merit, including suitable deuterated solvent, internal standard, quantitative peaks, and instrument acquisition parameters. Validation of the method using six different types of NPS afforded limits of detection of 0.05-0.1 mg/mL, limits of quantification of 0.01-0.03 mg/mL, repeatability and reproducibility lower than 0.5% and 3.6%, recoveries of 91.7%∼104.4%, and absence of matrix effect. The quantitative analysis of 65 seized chocolate samples by ¹H qNMR and ¹⁹F qNMR showed that the content of NPS was in the range of 0.5 mg/g∼44.1 mg/g. Generally, the developed qNMR method was simple, fast, precise, and can be performed without reference materials of NPS. Since the type and content of NPS are relatively random, chocolate consumers will face huge health risks. Therefore, this new trend of NPS-infused chocolate deserves and requires more attention from national NPS monitoring departments as well as forensic laboratories.

High-throughput quantitative binding analysis of DNA aptamers using exonucleases

Aptamers are nucleic acid bioreceptors that have been used in various applications including medical diagnostics and as therapeutic agents. Identifying the most optimal aptamer for a particular application is very challenging. Here, we for the first time have developed a high-throughput method for accurately quantifying aptamer binding affinity, specificity, and cross-reactivity via the kinetics of aptamer digestion by exonucleases. We demonstrate the utility of this approach by isolating a set of new aptamers for fentanyl and its analogs, and then characterizing the binding properties of 655 aptamer-ligand pairs using our exonuclease digestion assay and validating the results with gold-standard methodologies. These data were used to select optimal aptamers for the development of new sensors that detect fentanyl and its analogs in different analytical contexts. Our approach dramatically accelerates the aptamer characterization process and streamlines sensor development, and if coupled with robotics, could enable high-throughput quantitative analysis of thousands of aptamer-ligand pairs.

Development and application of a High-Resolution mass spectrometry method for the detection of fentanyl analogs in urine and serum

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Utilization of the fentanyl analog screening kit from the Centers for Disease ControlDevelopment of a fentanyl analog high resolution mass spectrometry library.

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Fentanyl analogs are rarely identified without the co-occurrence of fentanyl.

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Fentanyl analogs fragmentation occurs at two specific bonds generating two dominate ions.

Introduction

The use of illicitly manufactured synthetic opioids, specifically fentanyl and its analogs, has escalated exponentially in the United States over the last decade. Due to the targeted nature of drug detection methods in clinical laboratories and the ever-evolving list of synthetic opioids of concern, alternative analytical approaches are needed.

Methods

Using the fentanyl analog screening (FAS) kit produced by the Centers for Disease Control and Prevention (CDC), we developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) synthetic opioid spectral library and data acquisition method using information dependent acquisition of product ion spectra. Chromatographic retention times, limits of detection and matrix effects, in urine and serum, for the synthetic opioids in the FAS kit (n = 150) were established. All urine and serum specimens sent to a clinical toxicology laboratory for comprehensive drug testing in 2019 (n = 856) and 2021 (n = 878) were analyzed with the FAS LC-HRMS library to determine the prevalence of fentanyl analogs and other synthetic opioids, retrospectively (2019) and prospectively (2021).

Results

The limit of detection (LOD) of each opioid ranged from 1 to 10 ng/mL (median, 2.5 ng/mL) in urine and 0.25–2.5 ng/mL (median, 0.5 ng/mL) in serum. Matrix effects ranged from −79 % to 86 % (median, −37 %) for urine, following dilution and direct analysis, and −80 % to 400 % (median, 0 %) for serum, following protein precipitation. The prevalence of fentanyl/fentanyl analogs in serum samples increased slightly from 2019 to 2021 while it remained the same in urine. There were only 2 samples identified that contained a fentanyl analog without the co-occurrence of fentanyl or fentanyl metabolites. Analysis of the established MS/MS spectral library revealed characteristic fragmentation patterns in most fentanyl analogs, which can be used for structure elucidation and drug identification of future analogs.

Conclusions

The LC-HRMS method was capable of detecting fentanyl analogs in routine samples sent for comprehensive drug testing. The method can be adapted to accommodate testing needs for the evolving opioid epidemic.

Detection of 30 Fentanyl Analogs by Commercial Immunoassay Kits

Health-care workers, laboratorians and overdose prevention centers rely on commercial immunoassays to detect the presence of fentanyl; however, the cross-reactivity of fentanyl analogs with these kits is largely unknown. To address this, we conducted a pilot study evaluating the detection of 30 fentanyl analogs and metabolites by 19 commercially available kits (9 lateral flow assays, 7 heterogeneous immunoassays and 3 homogenous immunoassays). The analogs selected for analysis were compiled from the Drug Enforcement Administration and National Forensic Laboratory Information System reports from 2015 to 2018. In general, the immunoassays tested were able to detect their intended fentanyl analog and some closely related analogs, but more structurally diverse analogs, including 4-methoxy-butyryl fentanyl and 3-methylfentanyl, were not well detected. Carfentanil was only detected by kits specifically designed for its recognition. In general, analogs with group additions to the piperidine, or bulky rings or long alkyl chain modifications in the N-aryl or alkyl amide regions, were poorly detected compared to other types of modifications. This preliminary information is useful for screening diagnostic, forensic and unknown powder samples for the presence of fentanyl analogs and guiding future testing improvements.

Performance of Two Fentanyl Immunoassays against a Liquid Chromatography-Tandem Mass Spectrometry Method

Rapid and automated fentanyl screening assays are in need due to the prevalence of fentanyl abuse. In the present study, we evaluated the clinical performance of two FDA-cleared automated fentanyl immunoassays, the Immunalysis SEFRIA fentanyl assay and the ARK fentanyl assay. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) was used as a gold standard. Two groups of urine specimens were tested, including 225 specimens from patients presenting to the emergency department (ED) for whom urine drugs of abuse screens were ordered and 57 specimens from patients in chronic pain management programs. The SEFRIA assay generated higher assay imprecision than ARK assay (intraday CV%, 7.15 vs. 4.7%; interday CV%, 6.6 vs. 5.3%). Clinical sensitivity and specificity for detection of fentanyl exposure were 100 and 96% for the ARK assay and 95 and 80% for the SEFRIA assay. An 'auto-repeating' issue was observed for some validation specimens flagged with high absorbance values (OD > 3.0), generating false repeat results. The frequency of auto-repeating was lower in the ARK assay than SEFRIA (0.7 vs. 15.5%). Auto-repeating occurred for only previously frozen specimens in the ARK assay, but 9% of fresh specimens were also flagged and repeated in the SEFRIA assay. Positive predictive value (PPV) of the ARK assay was 73% in the ED population and 67% in the non-ED populations. The concentrations of fentanyl and norfentanyl were higher in specimens from ED patients than patients from pain management programs. High prevalence of morphine, methamphetamine, benzoylecgonine and 6-MAM was observed in specimens positive for fentanyl in both populations.

Prevalence of Stimulant, Hallucinogen, and Dissociative Substances Detected in Biological Samples of NPS-Intoxicated Patients in Italy

A number of new psychoactive substances (NPS) have been released in the last decade, and the list of NPS continues to grow. This paper reports a retrospective evaluation of the toxicological analyses in 1,445 suspected intoxication cases by psychostimulant, hallucinogen, and dissociative NPS occurring in hospitals across Italy from 2011 to 2019. The objectives of the study were to contribute to the monitoring of the NPS diffusion based on analytically confirmed intoxications, and to evaluate the importance of the clinical toxicological laboratory in the diagnosis of NPS intoxication. For at least one NPS of the considered classes, 246 patients (17.0%) tested positive. Forty-four different NPS were detected and a consistent turnover was observed during the nine-year period, especially regarding cathinones. Among the positive cases, 47.2% tested positive for dissociative NPS, with particular regard to ketamine. Hallucinogens (30.9%) was the second most frequent NPS involved. Stimulants were found in 20% of the positive cases with a considerable presence of cathinones. Findings confirm the dynamism of the NPS phenomenon, underline the importance of awareness of this new public health threat among health care professionals, and highlight the need for analytical confirmation for the identification of the drugs in forensic contexts.

Development and Clinical Validation of a Sensitive Lateral Flow Assay for Rapid Urine Fentanyl Screening in the Emergency Department

BACKGROUND

Rapid identification of fentanyl at the point-of-care is critical. Urine fentanyl concentrations in overdose cases start at single-digit nanograms per milliliter. No fentanyl point-of-care assay with a cutoff at single-digit nanograms per milliliter is available.

METHODS

A competitive lateral flow assay (LFA) was developed using gold nanoparticles and optimized for rapid screening of fentanyl in 5 minutes. Urine samples from 2 cohorts of emergency department (ED) patients were tested using the LFA and LC-MS/MS. The 2 cohorts consisted of 218 consecutive ED patients with urine drug-of-abuse screen orders and 7 ED patients with clinically suspected fentanyl overdose, respectively.

RESULTS

The LFA detected fentanyl (≥1 ng/mL) and the major metabolite norfentanyl (≥10 ng/mL) with high precision. There was no cross-reactivity with amphetamine, cocaine, morphine, tetrahydrocannabinol, methadone, buprenorphine, naloxone, and acetaminophen at 1000 ng/mL and 0.03%, 0.4%, and 0.05% cross-reactivity with carfentanil, risperidone, and 9-hydroxyrisperidone, respectively. In 218 consecutive ED patients, the prevalence of cases with fentanyl ≥1 ng/mL or norfentanyl ≥10 ng/mL was 5.5%. The clinical sensitivity and specificity of the LFA were 100% (95% CI, 75.8-100%) and 99.5% (95% CI, 97.3-99.9%), respectively. The positive and negative predictive values were 92.3% (95% CI, 66.7-98.6%) and 100% (95% CI, 98.2-100%), respectively. The concordance between the LFA and LC-MS/MS was 100% in the 7 suspected fentanyl overdose cases (5 positive, 2 negative).

CONCLUSIONS

The LFA can detect fentanyl and norfentanyl with high clinical sensitivity and specificity in the ED population with rapid fentanyl screening needs.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

Comparison of Two Commercially Available Fentanyl Screening Immunoassays for Clinical Use

BACKGROUND

Fentanyl is a synthetic opioid associated with illicit drug use and overdose deaths. The SEFRIA Immunalysis (IAL) and ARK fentanyl assays are both FDA-cleared, open channel immunoassays for fentanyl detection in urine. However, limited data are available in the literature comparing these assays. The objective of this study was to perform a direct comparison of these two fentanyl immunoassays.

METHODS

IAL and ARK fentanyl immunoassays were performed on a Roche Cobas e602 automated chemistry analyzer. Repeatability and total imprecision were compared by diluting fentanyl into urine at concentrations above, below, and at the manufacturers' cutoffs of 1.0 ng/mL. Cross-reactivity was assessed for norfentanyl and the fentanyl analogs acetylfentanyl, acrylfentanyl, and furanylfentanyl. Concordance was assessed in 90 patient samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the gold standard.

RESULTS

Repeatability varied from 11.4%-17.8% on the IAL assay and 2.8%-5.5% on the ARK assay. Total imprecision was 18.9%-40.7% on the IAL assay and 2.9%-6.4% on the ARK assay. Both assays cross-reacted with acetylfentanyl (∼100%), acrylfentanyl (∼100%), and furanylfentanyl (∼20%), but only the ARK assay cross-reacted with norfentanyl (∼3%). An admixture of 0.5 ng/mL fentanyl and 6 ng/mL norfentanyl produced a positive result on the ARK assay. Total concordance between IAL and ARK for 90 tested patient samples was 93% (kappa = 0.85). Relative to LC-MS/MS, the IAL assay had a concordance of 90% (kappa = 0.79) and the ARK assay had a concordance of 94% (kappa = 0.88). Including norfentanyl in the LC-MS/MS confirmation increased the concordance of the ARK to 96% (kappa = 0.90).

CONCLUSIONS

The ARK assay recognized the metabolite norfentanyl, demonstrated superior precision, and had better concordance with LC-MS/MS compared to the IAL assay.

Drug trends and harm related to new psychoactive substances (NPS) in Sweden from 2010 to 2016: Experiences from the STRIDA project

Background

In the past decade, hundreds of new psychoactive substances (NPS) have been introduced as unclassified alternatives to the illicit drugs. The NPS represent a growing health concern by causing adverse effects and deaths but are usually undetectable by conventional drug tests. This report summarizes results and experiences from analytically confirmed drug-related acute intoxications in emergency departments (ED) and intensive care units (ICU) enrolled in the Swedish STRIDA project on NPS in 2010–2016.

Methods and findings

ED/ICU intoxications suspected to involve NPS were enrolled in the project, after initial contact with the Poisons Information Centre (PIC). Serum/plasma and urine samples, and sometimes drug products, were subjected to a comprehensive toxicological investigation, and the PIC retrieved information on associated clinical symptoms and treatment. Between January 2010-February 2016, 2626 cases were enrolled. The patients were aged 8–71 (mean 27, median 24) years and 74% were men. Most biological samples (81%) tested positive for one, or more (70%), psychoactive drugs, including 159 NPS, other novel or uncommon substances, classical recreational and illicit drugs, and prescription medications. When first detected, most NPS or other novel substances (75%) were not banned in Sweden, but they usually disappeared upon classification, which however often took a year or longer. Some NPS were found to be especially harmful and even fatal.

Conclusions

The STRIDA project provided a good overview of the current drug situation in Sweden and demonstrated a widespread use and rapid turnover of many different psychoactive substances. The accomplishment of the project can be attributed to several key factors (close collaboration between the PIC and laboratory to identify suspected poisonings, free analysis, continuous updating of analytical methods, evaluation of adverse effects, and sharing information) that are useful for future activities addressing the NPS problem. The results also illustrated how drug regulations can drive the NPS market.

Investigation of Fragmentation Pathways of Fentanyl Analogues and Novel Synthetic Opioids by Electron Ionization High-Resolution Mass Spectrometry and Electrospray Ionization High-Resolution Tandem Mass Spectrometry

The global drug market is characterized by the fast development of new psychoactive substances such as fentanyl analogues and novel synthetic opioids, the detection of which is complicated by the lack of appropriate quality control procedures and references. Herein, we analyze the fragmentation pathways and characteristic ions of 25 novel fentanyl analogues and 5 novel synthetic opioids by electron ionization (EI) and electrospray ionization (ESI) high-resolution mass spectrometry to provide a reference for the identification of these species. In the ESI mode, fentanyl analogues mainly undergo piperidine ring degradation, phenethyl and piperidine ring dissociation, and piperidine ring and amide moiety cleavage, while piperidine ring degradation and phenethyl and piperidine ring dissociation are the major pathways in the EI mode. The five novel synthetic opioids largely undergo amide group dissociation and N-cyclohexyl bond cleavage in the ESI mode. Thus, this work facilitates the detection and quantitation of fentanyl analogues and novel synthetic opioids or other substances with similar structures in forensic laboratories.

Acute severe intoxication with cyclopropylfentanyl, a novel synthetic opioid

BACKGROUND

Since 2016 an increase has been observed in the availability of new synthetic opioids (NSO) in Europe. Cyclopropylfentanyl is a very potent and selective μ-opioid agonist, which was reported for the first time in August 2017 in Europe.

METHODS

The case was included in a prospective observational study of patients treated in emergency departments after the intake of novel psychoactive substances (NPS). Clinical features were acquired using a structured questionnaire for physicians. Serum and/or urine samples of ED patients were analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) screening methods for NPS.

CASE REPORT

Within 10 min after intranasal intake of fentanyl, a 25-year-old male developed nausea, profuse sweating and dyspnoe. Because soon afterwards coma and respiratory insufficiency was noticed, the patient was admitted to hospital. After administration of naloxone (0.8 mg) breathing stabilized. However, the patient displayed recurrent decreases of oxygen saturation for 12 h. The intake of cyclopropylfentanyl was analytically confirmed.

CONCLUSION

The constantly growing diversity of NSO still poses a high risk for drug users and can be a challenging task for clinicians and forensic toxicologists. Clinicians treating opioid overdoses should be aware of the potentially long lasting respiratory depression induced by fentanyl analogs.

Interpretation and Utility of Drug of Abuse Screening Immunoassays: Insights From Laboratory Drug Testing Proficiency Surveys

Context.—

Urine drug testing is frequently ordered by health care providers. Immunoassays are widely used for drug testing, yet have potential limitations, including variable cross-reactivity. The last decade has seen worsening of a prescription drug abuse epidemic.

Objective.—

To use data from a College of American Pathologists proficiency testing survey, Urine Drug Testing, Screening, to determine and summarize the characteristics, performance, and limitations of immunoassays.

Design.—

Seven years of proficiency surveys were reviewed (2011–2017).

Results.—

Rapid growth was seen in participant volumes for specific immunoassays for synthetic opioids (eg, buprenorphine, fentanyl, oxycodone) and 3,4-methylenedioxymethamphetamine (“ecstasy”). Participant volumes remained high for immunoassays targeting less commonly abused drugs such as barbiturates and phencyclidine. For opiate immunoassays, the number of laboratories using a 2000 ng/mL positive cutoff remained stable, and an increasing number adopted a 100 ng/mL cutoff. Opiate and amphetamine immunoassays showed high variability in cross-reactivity for drugs other than the assay calibrator. Assays targeting a single drug or metabolite generally performed well on drug challenges.

Conclusions.—

Survey results indicate strong clinical interest in urine drug testing and some adoption of new assays. However, urine drug testing availability does not parallel prevailing patterns of drug prescribing and abuse patterns. In particular, specific immunoassays for synthetic opioids and a lower positive cutoff for opiate immunoassays may be underused, whereas immunoassays for barbiturates, methadone, propoxyphene, and phencyclidine may be overused. Laboratories are encouraged to review their test menu, cutoffs, and assay performance and adjust their test offerings based on clinical needs and technical capabilities.

Novel synthetic opioids - toxicological aspects and analysis

Over the past few years, there has been an emerging number of new psychoactive drugs. These drugs are frequently mentioned as "legal highs", "herbal highs", "bath salts" and "research chemicals". They are mostly sold and advertised on online forums and on the dark web. The emerging new psychoactive substances are designed to mimic the effects of psychoactive groups, which are often abused drugs. Novel synthetic opioids are a new trend in this context and represent an alarming threat to public health. Given the wide number of fatalities related to these compounds reported within the last few years, it is an important task to accurately identify these compounds in biologic matrices in order to administer an effective treatment and reverse the respiratory depression caused by opioid related substances. Clinicians dealing with fentanyl intoxication cases should consider that it could, in fact, be a fentanyl analogue. For this reason, it is a helpful recommendation to include synthetic opioids in the routine toxicological screening procedures, including analysis in alternative matrices, if available, to investigate poly-drug use and possible tolerance to opioids. To address this public health problem, better international collaboration, effective legislation, effective investigation, control of suspicious "research chemicals" online forums and continuous community alertness are required. This article aims to review diverse reported fatalities associated with new synthetic opioids describing them in terms of pharmacology, metabolism, posology, available forms, as well as their toxic effects, highlighting the sample procedures and analytical techniques available for their detection and quantification in biological matrices.

Detectability of Dissociative Psychoactive Substances in Urine by Five Commercial Phencyclidine Immunoassays

Methoxetamine (MXE) and the arylcyclohexylamines 3-methoxy-PCP (3-MeO-PCP) and 4-methoxy-PCP (4-MeO-PCP) are substituted analogs of the dissociative psychoactive substances ketamine and phencyclidine (PCP), respectively. They have emerged on the new psychoactive substances (NPS) market as legal alternatives to these classically banned dissociatives. Little data has been published regarding the cross-reactivity of these NPS in PCP immunoassays (IAs). The aim of this work was to explore the possibilities of detecting 3-MeO-PCP, 4-MeO-PCP, MXE and ketamine in commercial IAs for PCP. The cross-reactivity study was performed in five different PCP IAs using urine-free, spiked samples and urine samples obtained from two 3-MeO-PCP overdose cases. 3-MeO-PCP and 4-MeO-PCP showed cross-reactivity (ranging from 1–143%) in all PCP IAs evaluated. MXE only showed very weak cross-reactivity (ranged from 0.04 to 0.25%) and ketamine was not detected in any PCP IA evaluated. Urine samples from the two overdose cases were positive for PCP in all IAs evaluated. The commercial PCP IAs evaluated exhibited utility as rapid, preliminary screening techniques for 3-MeO-PCP and 4-MeO-PCP, but not for ketamine. The low reactivity of MXE limits its detectability in the PCP IAs evaluated.

Ten Years of Fentanyl-like Drugs: a Technical-analytical Review

Synthetic opioids, such as fentanyl and its analogues, are a new public health warning. Clandestine laboratories produce drug analogues at a faster rate than these compounds can be controlled or scheduled by drug agencies. Detection requires specific testing and clinicians may be confronted with a sequence of severe issues concerning the diagnosis and management of these contemporary opioid overdoses. This paper deals with methods for biological sample treatment, as well as the methodologies of analysis that have been reported, in the last decade, in the field of fentanyl-like compounds. From this analysis, it emerges that the gold standard for the identification and quantification of 4-anilinopiperidines is LC-MS/MS, coupled with liquid-liquid or solid-phase extraction. In the end, the return to the scene of illicit fentanyls can be considered as a critical problem that can be tackled only with a global multidisciplinary approach.

Screening methods for rapid determination of new psychoactive substances (NPS) in conventional and non-conventional biological matrices

In the last years, a global awareness has arisen from the reported harmful effects and public health risks associated with the consumption of new psychoactive substances (NPSs). Improving efforts in the detection and identification of these substances have emerged as a global analytical challenge involving the large range of NPSs' chemical structures and the variety of conventional and non-conventional biological matrices. Indeed, detection capabilities and screening tools impact many fields and settings, including seized products analysis, workplace and roadside drug controls, emergency rooms, drug addiction treatment clinics, post-mortem and criminal caseworks, law enforcement and health interventions. Colorimetric, immunochemical and chromatographic-mass spectrometry techniques have been investigated and developed for the rapid identification of NPSs. Considering the continuous emergence of new substances, this review offers a panoramic view on the current status of analytical approaches for the rapid screening of NPSs, including, when available, data on conventional and non-conventional biological matrices. Although some of the presented methods are sound and promising, their applications are still limited, thus proving the importance of further investigations. New screening and sensitive targeted methods for NPS and their metabolites should be developed in different types of biological matrices, where concentration of substances and matrix effects can be significantly different.