Rapid detection of furanyl fentanyl in complex matrices using Leidenfrost desorption-assisted low-temperature arc plasma ionization mass spectrometry.

The abuse of illicit drugs poses serious threats to the physical and mental health of users, as well as to the overall safety and welfare of society. In this work, we present a newly developed technique for drug detection based on mass spectrometry. This technique combines Leidenfrost desorption with low-temperature arc plasma ionization mass spectrometry. This method is applicable for detecting furanyl fentanyl in complex matrices. Key advantages of this technique include minimal sample fragmentation and high sensitivity for detection. The Leidenfrost desorption plays a pivotal role in this methodology, as it spontaneously concentrates analyte molecules during the gradual evaporation of the solvent. Eventually, these concentrated molecules are redistributed at their highest concentrations, resulting in exceptionally high sensitivity. In the course of our investigation, we achieved a remarkable detection limit of 10 pg mL-1 for furanyl fentanyl in pure water. Moreover, the characteristic ion peaks of furanyl fentanyl can be distinctly identified within complex matrices such as wine, beverages, urine, and lake water. This innovative drug detection technology offers several advantages, including a simple setup, cost-effectiveness, rapid detection, high sensitivity, and minimal sample pretreatment.

Tackling new psychoactive substances through metabolomics: UHPLC-HRMS study on natural and synthetic opioids in male and female murine models.

Novel psychoactive substances (NPS) represent a broad class of drugs new to the illicit market that often allow passing drug-screening tests. They are characterized by a variety of structures, rapid transience on the drug scene and mostly unknown metabolic profiles, thus creating an ever-changing scenario with evolving analytical targets. The present study aims at developing an indirect screening strategy for NPS monitoring, and specifically for new synthetic opioids (NSOs), based on assessing changes in endogenous urinary metabolite levels as a consequence of the systemic response following their intake. The experimental design involved in-vivo mice models: 16 animals of both sex received a single administration of morphine or fentanyl. Urine was collected before and after administration at different time points; the samples were then analysed with an untargeted metabolomics LC-HRMS workflow. According to our results, the intake of opioids resulted in an elevated energy demand, that was more pronounced on male animals, as evidenced by the increase in medium and long chain acylcarnitines levels. It was also shown that opioid administration disrupted the pathways related to catecholamines biosynthesis. The observed alterations were common to both morphine and fentanyl: this evidence indicate that they are not related to the chemical structure of the drug, but rather on the drug class. The proposed strategy may reinforce existing NPS screening approaches, by identifying indirect markers of drug assumption.

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.

Strong π-Metal Interaction Enables Liquid Interfacial Nanoarray-Molecule Co-assembly for Raman Sensing of Ultratrace Fentanyl Doped in Heroin, Ketamine, Morphine, and Real Urine.

Toward the challenge on reliable determination of trace fentanyl to avoid opioid overdose death in drug crisis, here we realize rapid and direct detection of trace fentanyl in real human urine without pretreatment by a portable surface enhanced Raman spectroscopy (SERS) strategy on liquid/liquid interfacial (LLI) plasmonic arrays. It was observed that fentanyl could interact with the gold nanoparticles (GNPs) surface, facilitate the LLI self-assembly, and consequently amplify the detection sensitivity with a limit of detection (LOD) as low as 1 ng/mL in aqueous solution and 50 ng/mL spiked in urine. Furthermore, we achieve multiplex blind sample recognition and classification of ultratrace fentanyl doped in other illegal drugs, which has extremely low LODs at mass concentrations of 0.02% (2 ng in 10 µg of heroin), 0.02% (2 ng in 10 µg of ketamine), and 0.1% (10 ng in 10 µg of morphine). A logic circuit of the AND gate was constructed for automatic recognition of illegal drugs with or without fentanyl doping. The data-driven analog soft independent modeling model could quickly distinguish fentanyl-doped samples from illegal drugs with 100% specificity. Molecular dynamics (MD) simulation elucidates the underlying molecular mechanism of nanoarray-molecule co-assembly through strong π-metal interactions and the differences in the SERS signal of various drug molecules. It paves a rapid identification, quantification, and classification strategy for trace fentanyl analysis, indicating broad application prospects in response to the opioid epidemic crisis.

Update: Correlation of Fentanyl Positive Drug Screens with other Medications in Patients from Pain, Rehabilitation and Behavioral Programs.

OBJECTIVE: To monitor fentanyl polydrug use over past six years. METHOD: Calculate percent of fentanyl and other drugs positive in urine drug tests. RESULTS: Percent of fentanyl positive drug tests remained unchanged, but increases in fentanyl/methamphetamine and fentanyl/marijuana were observed. CONCLUSIONS: Fentanyl laced illicit drugs remain a major substance abuse problem.

Bupivacaine Metabolite Can Interfere with Norfentanyl Measurement by LC-MS/MS.

BACKGROUND: Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is the gold standard for the measurement of fentanyl and norfentanyl (NF) in urine and is favored over immunoassays due to its superior specificity. NF is the principal metabolite of fentanyl found in the urine and is typically present in higher abundance than fentanyl. Thus, the sensitivity and specificity of LC-MS/MS relies largely on the ability to identify and quantitate NF. METHODS: We analyzed urine specimens from women who had received bupivacaine and fentanyl for epidural analgesia during labor. We analyzed the contents of the epidural bag itself and purified bupivacaine metabolite N-desbutyl bupivacaine [or N-(2,6-dimethylphenyl)piperidine-2-carboxamide (NDB)] by LC-MS/MS. RESULTS: NDB interferes with the LC-MS/MS assay for NF. NDB passes through the Q1 mass selection filter because it is isobaric with the NF precursor ion (233 m/z). Further, it shares product ions with NF (84 m/z and 150 m/z), used as quantifier and qualifier ions, respectively, in our urine NF detection method. Baseline resolution of NDB and NF using these quantifier and qualifier ions could not be achieved. A unique product ion of NF (177 m/z) was useful for distinguishing NDB from NF. CONCLUSION: Bupivacaine is a commonly used drug. Recognition of this interference by laboratories is critical for preventing the misidentification of NF, which can have profound effects on patient care.

Polysubstance Use Among Patients Treated With Buprenorphine From a National Urine Drug Test Database.

Importance: Polysubstance use is a concern for patients treated for opioid use disorder (OUD). While buprenorphine can curtail harmful opioid use, co-occurring use of nonprescribed substances, such as cocaine, methamphetamine, and other opioids, may negatively affect treatment outcomes. Objective: To characterize factors associated with urine drug positivity for nonprescribed substances among patients prescribed buprenorphine. Design, Setting, and Participants: This cross-sectional study included patients who had been prescribed buprenorphine and who provided urine specimens for urine drug testing (UDT), as ordered by clinicians in primary care or behavioral health or at substance use disorder treatment centers, from 2013 to 2019. Specimens were analyzed by liquid chromatography-tandem mass spectrometry to assess positivity for several commonly used substances. Exposures: Buprenorphine prescription. Main Outcomes and Measures: Positivity for buprenorphine and several nonprescribed substances. Unadjusted trends in positivity for each nonprescribed substance were compared between specimens that did and did not test positive for buprenorphine. Multivariable logistic regression was used to examine factors associated with positivity; factors included patient age, sex, setting of care, payer, collection year, and census division. Results: The study included first UDT specimens from 150 000 patients, of whom 82 107 (54.74%) were men and 77 300 (51.53%) were aged 18 to 34 years. Across all specimens, 128 240 (85.49%) were positive for buprenorphine, and 71 373 (47.58%) were positive for 1 or more nonprescribed substances. From 2013 to 2019, positivity rates increased for most substances (eg, fentanyl: from 131 of 21 412 [0.61%] to 1464 of 13 597 [10.77%]). Factors associated with positivity varied widely by substance; for example, fentanyl positivity was highest for men (OR, 1.13; 95% CI, 1.06-1.21), patients aged 18 to 24 years (OR for patients ≥55 years, 0.46; 95% CI, 0.39-0.54), patients living in New England (OR, 1.19; 95% CI, 1.07-1.33), and patients with Medicaid (OR, 1.20; 95% CI, 1.11-1.31), whereas oxycodone positivity was greatest for women (OR for men, 0.84; 95% CI, 0.79-0.89), patients older than 55 years (OR, 1.42; 95% CI, 1.22-1.64), patients living in the South Atlantic (OR, 1.45, 95% CI, 1.33-1.58), and patients with private insurance (OR for Medicaid, 0.78; 95% CI, 0.73-0.84). Patients whose specimens were positive for buprenorphine were significantly less likely to be positive for other opioids (eg, fentanyl: OR for buprenorphine-negative samples, 6.71; 95% CI, 6.29-7.16; heroin: OR for buprenorphine-negative samples, 9.93; 95% CI, 9.31-10.59). Conclusions and Relevance: In this cross-sectional study, patterns of nonprescribed substance positivity among patients prescribed buprenorphine varied widely. This study highlights the utility of UDT in public health surveillance efforts related to patients treated with buprenorphine for OUD.

Untargeted Metabolomics in Forensic Toxicology: A New Approach for the Detection of Fentanyl Intake in Urine Samples.

The misuse of fentanyl, and novel synthetic opioids (NSO) in general, has become a public health emergency, especially in the United States. The detection of NSO is often challenged by the limited diagnostic time frame allowed by urine sampling and the wide range of chemically modified analogues, continuously introduced to the recreational drug market. In this study, an untargeted metabolomics approach was developed to obtain a comprehensive "fingerprint" of any anomalous and specific metabolic pattern potentially related to fentanyl exposure. In recent years, in vitro models of drug metabolism have emerged as important tools to overcome the limited access to positive urine samples and uncertainties related to the substances actually taken, the possible combined drug intake, and the ingested dose. In this study, an in vivo experiment was designed by incubating HepG2 cell lines with either fentanyl or common drugs of abuse, creating a cohort of 96 samples. These samples, together with 81 urine samples including negative controls and positive samples obtained from recent users of either fentanyl or "traditional" drugs, were subjected to untargeted analysis using both UHPLC reverse phase and HILIC chromatography combined with QTOF mass spectrometry. Data independent acquisition was performed by SWATH in order to obtain a comprehensive profile of the urinary metabolome. After extensive processing, the resulting datasets were initially subjected to unsupervised exploration by principal component analysis (PCA), yielding clear separation of the fentanyl positive samples with respect to both controls and samples positive to other drugs. The urine datasets were then systematically investigated by supervised classification models based on soft independent modeling by class analogy (SIMCA) algorithms, with the end goal of identifying fentanyl users. A final single-class SIMCA model based on an RP dataset and five PCs yielded 96% sensitivity and 74% specificity. The distinguishable metabolic patterns produced by fentanyl in comparison to other opioids opens up new perspectives in the interpretation of the biological activity of fentanyl.

Determination of nine new fentanyl analogues and metabolites in consumers' urine by ultra-high-performance liquid chromatography-tandem mass spectrometry.

OBJECTIVE: New fentanyl analogues have been constantly emerging into the illegal drug market as cheap substitutes of heroin posing a serious health threat for consumers because of their high toxicity. Analytical methods to disclose the presence of these compounds in biological fluids of intoxicated individuals need to be updated to keep up with the new trends. In this study, we updated an ultra-high-performance liquid chromatography-tandem mass spectrometry method previously developed, for detecting some new fentanyl analogues and metabolites (sufentanil and norsufentanil, cis-3-methylnorfentanyl, trans-3-methylnorfentanyl, metabolites of cis and transmethylfentanyl, beta-phenylfentanyl, phenylfentanyl, para-fluoro furanyl fentanyl, isobutyryl fentanyl and ocfentanil) in urine sample. MATERIALS AND METHODS: Urine samples were simply diluted before injection in the chromatograph equipped with a reversed phase microcolumn. Detection was achieved with a triple quadrupole mass spectrometer with an electrospray ionization source in positive ion mode and operated in multiple reaction monitoring. RESULTS: The chromatographic separation was short (5 min) and the method was fully validated with a high sensitivity being limits of quantifications from 0.003 to 0.006 µg/L urine for the analytes under investigation. CONCLUSIONS: The suitability of the method was tested with urine specimens from former heroin addicts, which resulted positive by immunological screening to the class of fentanyl analogues. This method represents a valid tool to document recent exposure to the above-reported compounds for clinical and forensic purposes.

Evidence of increased Fentanyl use during the COVID-19 pandemic among opioid agonist treatment patients in Ontario, Canada.

BACKGROUND: Amid the opioid crisis, the health care system is restructuring to prevent and treat COVID-19. Individuals in opioid agonist treatment (OAT) are uniquely challenged because of disruption to treatment, medication diversion, and isolation during the pandemic. METHODS: Between January and September 2020, we utilized the electronic medical record from a chain of 67 opioid agonist treatment clinics in Ontario, Canada, to examine routinely collected urine drug screen results of patients in opioid agonist treatment by Public Health Units. RESULTS: We present evidence of a 108% increase in the percentage of fentanyl positive urine drug screens from April to September (p< 0.001). During the same period, health regions in northern and southwestern Ontario, areas with a high concentration of rural communities, have seen the most notable increase in the percent of fentanyl positive urine drug screen results. CONCLUSION: The use of fentanyl increased by 108% among OAT patients in Ontario during the COVID 19 pandemic. We argue that the persistent increase of fentanyl exposure over time, specifically in the OAT population, suggests that reduced monitoring may decrease OAT's effectiveness and negatively impact patient outcomes.

Structure Elucidation of Urinary Metabolites of Fentanyl and Five Fentanyl Analogs using LC-QTOF-MS, Hepatocyte Incubations and Synthesized Reference Standards.

Fentanyl analogs constitute a particularly dangerous group of new psychoactive compounds responsible for many deaths around the world. Little is known about their metabolism, and studies utilizing liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis of hepatocyte incubations and/or authentic urine samples do not allow for determination of the exact metabolite structures, especially when it comes to hydroxylated metabolites. In this study, seven motifs (2-, 3-, 4- and ß-OH as well as 3,4-diOH, 4-OH-3-OMe and 3-OH-4-OMe) of fentanyl and five fentanyl analogs, acetylfentanyl, acrylfentanyl, cyclopropylfentanyl, isobutyrylfentanyl and 4F-isobutyrylfentanyl were synthesized. The reference standards were analyzed by LC-QTOF-MS, which enabled identification of the major metabolites formed in hepatocyte incubations of the studied fentanyls. By comparison with our previous data sets, major urinary metabolites could tentatively be identified. For all analogs, ß-OH, 4-OH and 4-OH-3-OMe were identified after hepatocyte incubation. ß-OH was the major hydroxylated metabolite for all studied fentanyls, except for acetylfentanyl where 4-OH was more abundant. However, the ratio 4-OH/ß-OH was higher in urine samples than in hepatocyte incubations for all studied fentanyls. Also, 3-OH-4-OMe was not detected in any hepatocyte samples, indicating a clear preference for the 4-OH-3-OMe, which was also found to be more abundant in urine compared to hepatocytes. The patterns appear to be consistent across all studied fentanyls and could serve as a starting point in the development of methods and synthesis of reference standards of novel fentanyl analogs where nothing is known about the metabolism.

Brief Report: Rates of Fentanyl Use Among Psychiatric Emergency Room Patients.

BACKGROUND AND OBJECTIVES: Opioid overdose-related deaths increased from approximately 18 000 deaths in 2007 to 46 802 deaths in 2018. Fentanyl is primarily responsible for the increase in opioid overdose deaths from 2011 through 2017. The primary aim of this study is to determine the rates of fentanyl in the urine drug screens of all patients who presented to the psychiatric emergency room at VA Connecticut, over 7 months in 2018. METHODS: Data were collected for all patient presentations between June 2018 and December 2018. There were 746 total patient presentations, with 497 being unique. Collected data included basic demographic information, psychiatric diagnosis, and urine drug screen for various illicit substances, including fentanyl. RESULTS: Over 15% of patients screened positive for fentanyl. Patients who tested positive for fentanyl were further classified based on positive urine drug screening results for other opioids, cocaine, or both. Twenty percent of patients who screened positive for fentanyl and cocaine tested negative for other opioids. This category suggests that some veterans might be consuming fentanyl with cocaine. DISCUSSION AND CONCLUSIONS: Fentanyl was found at a high rate, even in the absence of other opioids, which suggests that some veterans might be consuming fentanyl with cocaine. Consequently, harm reduction strategies should be broadened to include all patients at risk of fentanyl overdose, including patients who use substances (eg, cocaine) that are potentially adulterated with fentanyl. SCIENTIFIC SIGNIFICANCE: This study is the first one of its kind that looked at rates of fentanyl use in all presentations to a psychiatric emergency room. While it is well-known that fentanyl is highly prevalent, these findings extend the current state of knowledge by replication in a psychiatric emergency population. (Am J Addict 2021;30:92-95).

The Increasing Prevalence of Fentanyl: A Urinalysis-Based Study Among Individuals With Opioid Use Disorder in New York City.

BACKGROUND AND OBJECTIVES: Opioid-related overdose deaths in North America have increased drastically, partially due to the increased prevalence of illicitly manufactured fentanyl. The current study sought to assess the prevalence and intentionality of fentanyl use among individuals with opioid use disorder (OUD). METHODS: For this secondary analysis (study 1) we screened a total of 1118 urine samples from 316 participants with OUD from 2016 to 2019. Fentanyl knowledge and intentionality of use were assessed in a separate OUD sample (study 2; N = 33). RESULTS: In study 1, 34.6% of all urine samples tested positive for fentanyl. Overall, 149 (47.2%) participants provided more than or equal to one urine sample that tested fentanyl-positive, and 93 (29.4%) provided more than or equal to two fentanyl-positive samples. The number of fentanyl-positive samples, relative to the number of samples tested each year, increased by 330% from year 1 to 3. Study 2 found all participants had pre-existing knowledge that drugs may be adulterated with fentanyl, yet 67% were surprised by their own fentanyl-positive test result. DISCUSSION AND CONCLUSIONS: Like previous studies, our data indicate the high prevalence of fentanyl exposure and low perception of fentanyl-related risk among individuals with OUD, respectively, suggesting that opioid overdose harm reduction efforts may need to focus more on drug users' understanding of risks related to fentanyl use and adulteration of drugs. SCIENTIFIC SIGNIFICANCE: The current studies provide longitudinal data on fentanyl exposure prevalence and risk perception that is uniquely granular by assessing OUD treatment status, and by identifying potential associations between fentanyl exposure with the presence of other drug use and nonfatal overdose. (Am J Addict 2021;30:65-71).

The Opioid Epidemic Within the COVID-19 Pandemic: Drug Testing in 2020.

The convergence of the opioid epidemic and the coronavirus disease 2019 (COVID-19) pandemic has created new health care challenges. The authors analyzed changes in clinical drug testing patterns and results at a national clinical laboratory, comparing data obtained before and during the pandemic. Testing for prescription and illicit drugs declined rapidly during the pandemic, with weekly test volumes falling by approximately 70% from the baseline period to the trough (the week beginning March 29) before rising in subsequent weeks. Among individuals tested, positivity increased by 35% for non-prescribed fentanyl and 44% for heroin during the pandemic. Positivity for non-prescribed fentanyl increased significantly among patients positive for other drugs: by 89% for specimens positive for amphetamines; 48% for benzodiazepines; 34% for cocaine; and 39% for opiates (P < 0.01 for all comparisons). These findings suggest significant increases in dangerous drug combinations. Positivity for non-prescribed use of many other drugs remained consistent or declined for some drugs, relative to pre-pandemic patterns. Models adjusting for potential confounding variables, including medication-assisted treatment and treatment at a substance use disorder facility indicated that the risk for non-prescribed fentanyl positivity rose by more than 50% during the pandemic. In summary, these findings demonstrate decreased drug testing overall, with increased positivity for high-risk drugs and dangerous drug combinations. The convergence of the drug abuse epidemic and COVID-19 pandemic has led to an increased need for health care and public health resources dedicated to supporting vulnerable patients and addressing the underlying causes of these disturbing trends.

Multiplex detection of 14 fentanyl analogues and U-47700 in biological samples: Application to a panel of French hospitalized patients.

Synthetic opioids (SO) associated with the recent alarming increase of deaths and intoxications in United States of America and Europe are not detected by the usual first-line opiates drug screening assays. We developed a liquid chromatography tandem mass spectrometry analytical method for the multiplex detection of 14 fentanyl analogues (2-furanylfentanyl, 4-ANPP, 4-methoxybutyrylfentanyl, acrylfentanyl, alfentanil, carfentanil, despropionyl-2-fluorofentanyl, fentanyl, methoxyacetylfentanyl, norfentanyl, ocfentanil, remifentanil, sufentanil and valerylfentanyl) and U-47700 in whole blood and urine samples. The method was validated according to the requirements of ISO 15189. A simple and fast liquid-liquid extraction (LLE) with De-Tox Tube-A was performed leading to better recovery of molecules in urine than in blood samples. Depending on the compound, the limits of detection (LODs) ranged from 0.01 to 0.10 ng/mL and from 0.02 to 0.05 ng/mL in whole blood and urine, respectively. Calibration curves were linear in the range 0.5-50.0 ng/mL and the limit of quantification (LOQ) ranged from 0.10 to 0.40 ng/mL in blood. Internal quality controls at 1 and 40 ng/mL showed intra-day and between-day precision and accuracy bias below 10% in urine and 15% in blood. The method was applied to the screening of 211 urine samples from patients admitted in emergency or addiction departments. The presence of legal fentanyl analogues in 5 urine samples was justified by their therapeutic use as analgesics. Only one patient was concerned by fentanyl misuse and addiction whereas no illegal SO was detected. This study is not in favor of a huge misuse of SO in the Lorraine region.

Delayed Norfentanyl Clearance During Pregnancy.

BACKGROUND: We report a case of delayed norfentanyl clearance in a 33-year-old pregnant woman. Norfentanyl is the major metabolite of fentanyl. CASE: A multigravid woman with opioid use disorder presented at 7 weeks of gestation for treatment. Despite opioid abstinence, her urine was positive for norfentanyl on 10 distinct gas chromatography-mass spectrometry urine screens. The results demonstrated a steady decrease of norfentanyl over the course of 70 days after her last fentanyl usage, far exceeding expected rates of fentanyl clearance. CONCLUSION: This case highlights the importance of acknowledging pregnancy, genetic, or medication-induced changes to fentanyl pharmacokinetics when interpreting urine tests, especially given the potential sequelae of a false-positive urine test result.

Fentanyl analog positivity among near-real-time urine drug test results in patients seeking health care.

Overdose deaths involving synthetic opioids continue to climb. Fentanyl analogs have been identified as important contributors to these overdoses, but little is known about their prevalence in patients seeking health care. This cross-sectional study of urine drug test (UDT) results from July 15, 2019, through March 12, 2020, included patient specimens analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), submitted by health care professionals as part of routine care to detect fentanyl and fentanyl analogs. A convenience sample approach was used to select patient specimens from diverse health care practices across all 50 states, then stratified by fentanyl prescription status. Positivity rates, geographic distribution, and co-occurrence were quantified. The total positivity rate for ten fentanyl analogs was 40.55% in the non-prescribed fentanyl-positive population. The most common fentanyl analogs in this population were 4-ANPP (4-anilino-N-phenethylpiperidine), 30.74%; acetyl fentanyl, 19.40%; and carfentanil, 3.13%. The total positivity rate for four fentanyl analogs was 8.93% in the prescribed fentanyl-positive population, including 4-ANPP, 8.85%; acetyl fentanyl, 0.19%; acryl fentanyl, 0.05%; and 4-FiBF, 0.03%. Counties in Ohio and Kentucky had the highest positivity rates. Acetyl fentanyl and 4-ANPP copositivity occurred in 11.36% of non-prescribed patient specimens. However, acetyl fentanyl and 4-ANPP positivity may not be consistent with fentanyl analog use since both are process impurities, and 4-ANPP is a metabolite of fentanyl. Near-real-time, definitive UDT results reveal fentanyl analogs in patients seeking health care, helping clinicians and public health officials better understand their contribution to overdoses and help mitigate the risks they pose.

Rapid quantitative determination of fentanyl in human urine and serum using a gold-based immunochromatographic strip sensor.

Fentanyl is a typical opioid that is used in surgical anesthesia. However, when abused, fentanyl can lead to addiction and even death. To better control the use of fentanyl, it is necessary to develop rapid and sensitive detection methods. In this study, an ultrasensitive monoclonal antibody (mAb) was prepared and used to develop an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and a colloidal gold-based immunochromatographic strip (CG-ICS) for the analysis of fentanyl in urine and serum. Under optimum conditions, the anti-fentanyl mAb belonging to the subtype of IgG2b showed a half-maximal inhibitory concentration (IC50) of 0.11 ng mL-1 and a linear range of detection of 0.020-0.50 ng mL-1. Fenanyl-spiked original urine and serum diluted eight times were used for the analysis of fentanyl by ic-ELISA and CG-ICS. IC50 from the standard curves was 0.46 ng mL-1 for urine and 2.6 ng mL-1 for serum in ic-ELISA and 1.6 ng mL-1 for urine and 6.27 ng mL-1 for serum in CG-ICS. The recovery test revealed that the ic-ELISA and CG-ICS, with a recovery rate of 87.0-108.4% and a coefficient of variation of 3.3-10.9%, were the same reliable tools as the liquid chromatography tandem mass spectrometry for fentanyl analysis in real samples.