Comprehensive toxicological screening of common drugs of abuse, new psychoactive substances and cannabinoids in blood using supported liquid extraction and liquid chromatography-quadrupole time-of-flight mass spectrometry

Immunoassay (IA) is currently the most widely used technique for toxicological screening in drug-impaired driving investigations. However, practical limitations in the scope of testing, and the emergence of new psychoactive substances (NPSs), have highlighted the need for alternative approaches, particularly mass spectrometry-based screening. High-resolution mass spectrometry broadens the scope of testing to include NPSs and increases analyte specificity compared to IA. In addition, it provides a platform with increased flexibility and adaptability to incorporate emerging drugs of interest due to the transient drug market. In this study, a comprehensive screening procedure was developed to identify >200 drugs of interest, including cannabinoids and NPSs in whole blood. Supported liquid extraction and liquid chromatography-quadrupole time-of-flight mass spectrometry using All Ions data acquisition were used. The method was validated in accordance with published recommendations, and all compounds of interest were identified at recommended cutoffs for driving under the influence of drug investigations. Cannabinoids, including 11-nor-9-carboxy-∆9-tetrahydrocannabinol, fentanyl analogs, buprenorphine, novel synthetic opioids and synthetic cannabinoids, were identified at low- to sub-nanogram/milliliter concentrations in whole blood using both positive and negative electrospray ionization acquisition methods.

Mitigating Matrix Effects in LC-ESI-MS-MS Analysis of a Urinary Biomarker of Xylenes Exposure

Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) with stable isotope-labeled internal standards (SIL-ISs) is the gold standard for quantitative analysis of drugs and metabolites in complex biological samples. Significant isotopic effects associated with deuterium labeling often cause the deuterated IS to elute at a different retention time from the target analyte, diminishing its capability to compensate for matrix effects. In this study, we systematically compared the analytical performance of deuterated (2H) SIL-IS to non-deuterated (13C and 15N) SIL-ISs for quantifying urinary 2-methylhippuric acid (2MHA) and 4-methylhippuric acid (4MHA), biomarkers of xylenes exposure, with an LC-ESI-MS-MS assay. Analytical method comparison between ISs demonstrated a quantitative bias for urinary 2MHA results, with concentrations generated with 2MHA-[2H7] on average 59.2% lower than concentrations generated with 2MHA-[13C6]. Spike accuracy, measured by quantifying the analyte-spiked urine matrix and comparing the result to the known spike concentration, determined that 2MHA-[2H7] generated negatively biased urinary results of -38.4%, whereas no significant bias was observed for 2MHA-[13C6]. Post-column infusion demonstrated that ion suppression experienced by 2MHA and 2MHA-[13C6] was not equally experienced by 2MHA-[2H7], explaining the negatively biased 2MHA results. The quantitation of urinary 4MHA results between ISs exhibited no significant quantitative bias. These results underscore the importance of the careful selection of ISs for targeted quantitative analysis in complex biological samples.

Novel Matrix Normalization Technique for Accurate LC-ESI-MS/MS Detection and Quantification of Drugs and Their Metabolites in Toxicology Research and Practice

Accurate identification and quantification of drugs and their metabolites (analytes) in biological matrices is an analytical foundation of clinical and forensic toxicology. For decades, liquid chromatography interfaced by electrospray ionization with tandem mass spectrometry (LC-ESI-MS/MS) has been a widely used technology for analysis in the field of toxicology, as well as in many other fields of bioscience. It is also known that ion response in LC-ESI-MS/MS analysis is influenced by coeluting biological compounds and that preanalytical sample clean-up is often insufficient in removing these interferences. As a result, a normalization technique is commonly used for assessment and compensation of matrix effects encountered in routine analysis. Internal standardization with a stable isotope analog of the analyte is the predominant normalization technique used in LC-ESI-MS/MS analysis. The technique, however, requires commercial availability or costly custom synthesis of an isotopic analog specific for each analyte. Here we describe an alternative technique for matrix normalization for use in high-volume, multianalyte testing without the need for isotope analogs. The technique involves analysis of the original sample (neat analysis) followed by analysis of a second sample aliquot (spike analysis) that has been fortified with a controlled amount of reference analyte. A calibration procedure similar to internal standardization is employed, using an ion response ratio of neat to fortified analyte. As a demonstration of the technique in multianalyte testing, we provide a detailed protocol for simultaneous detection and quantification of 102 drugs and drug metabolites in human urine. We also provide a support protocol for addition of new analytes to the multianalyte panel, allowing convenient collection of the validation data during routine testing. The matrix normalization technique and testing principles may be applicable to a wide range of analytes and biological matrices, not only those encountered in toxicology but also in other fields of bioscience. © 2023 Wiley Periodicals LLC. Basic Protocol: Detection and quantification of 102 toxicology analytes in urine by LC-ESI-MS/MS analysis using the threshold accurate calibration technique Support Protocol: Method for addition and validation of new analytes to expand the Basic Protocol.

Application and Clinical Value of Definitive Drug Monitoring in Pain Management and Addiction Medicine

OBJECTIVE

To assess routine application and clinical value of definitive urine drug monitoring (UDM) for drug detection, inconsistent drug use and prescription adherence, along with a comparison to immunoassay screening (IAS).

METHODS

Direct-to-definitive UDM performance was analyzed retrospectively in 5,000 patient specimens. Drug findings, medication inconsistencies and detection sensitivity were assessed, and definitive UDM versus IAS monitoring was studied.

RESULTS

Definitive testing resulted in 18,793 drug findings with 28,403 positive drug and metabolite tests. Definitive testing expanded monitoring with 11,396 drug findings that would not be tested by IAS. The opioids accounted for the highest frequency of inconsistent positive drug-use findings, at 12%. Conversely, inconsistent negative drug findings, used as an index of prescription non-adherence, were determined in 1,751 of 15,409 monitored medications and included a high frequency of antidepressants and antipsychotics inconsistencies. Direct comparison of definitive UDM and IAS showed false-positives by IAS as well as a high rate of false-negatives that would be missed using current confirmation protocols.

CONCLUSIONS

Results from routine application of direct-to-definitive UDM demonstrate the clinical value of drug-use identification and objective evaluation of inconsistencies in drug misuse and medication adherence in pain management and addiction medicine practice. Without conversion to direct-to-definitive UDM, continuing use of IAS will limit the scope of drugs being tested, will result in an indeterminate rate of false negatives and will require confirmation testing to eliminate the reporting of false positive IAS tests. The findings in this study provide evidence-based support for recommended use of a direct-to-definitive drug testing protocol.

Strategic Decision-Making by a Forensic Toxicology Laboratory in Response to an Emerging NPS: Detection, Quantitation and Interpretation of Carfentanil in Death Investigations in Ontario, Canada, July 2017 to June 2018

The proliferation of novel psychoactive substances (NPS) and the current opioid epidemic creates challenges for a toxicology laboratory. Methods capable of detecting and quantitating emerging compounds must be established despite limited information on toxicologically relevant concentrations. This paper will (i) describe how a publicly funded forensic laboratory reacted to the emergence of carfentanil as a public safety concern and (ii) contribute to the existing forensic literature by presenting a series of deaths involving carfentanil between July 2017 and June 2018. The Centre of Forensic Sciences is the primary provider of forensic toxicology testing in medicolegal death investigations in the province of Ontario. When carfentanil was first identified in the illicit drug supply, routine screening methods used by this laboratory were not sufficiently sensitive to detect the drug at concentrations expected in blood samples. Previously validated, multi-target liquid chromatography-tandem mass spectrometry (LC-MS-MS) quantitative methods already in use by the laboratory did show improved detectability for carfentanil. Thus, an existing LC-MS-MS method was adapted to include carfentanil, achieving improved sensitivity while also providing quantitation in suspected drug-related deaths. This approach had the added benefit that the LC-MS-MS method selected for modification was used in all death investigations requiring toxicology analysis in Ontario, thereby providing an opportunity for surveillance. Using this method, 4,953 cases were analyzed with carfentanil detected at a concentration greater than the limit of detection (0.05 ng/mL) in 160 decedents. Postmortem blood carfentanil concentrations ranged from less than 0.1 to 9.2 ng/mL. Of the 160 carfentanil-positive cases, 156 were classified as either mixed drug toxicity or carfentanil overdose. The approach described enabled this laboratory to efficiently implement a quantitative test for carfentanil in all death investigations, providing a useful template for modifying existing methods when a new psychoactive substance becomes available in the population.

Matrix Normalization Techniques for Definitive Urine Drug Testing

Analytical performance of stable isotope labeled internal standardization (SIL-IS) and threshold accurate calibration (TAC) methods of matrix normalization are compared for quantitation of 51 drugs and metabolites (analytes) in urine with analysis by UPLC-MS-MS. SIL-IS was performed with both analyte-specific (ASIL-IS) and shared (SSIL-IS) internal standards. Variance in inter-specimen matrix effect, without use of a matrix normalization method, was studied by UPLC-MS-MS (Ultra Performance Liquid Chromatography with tandem mass spectrometry) analysis of 338 urine donor samples and showed over 200% variation in ion response for some analytes. Matrix normalization methods were evaluated for precision, accuracy, calibration, multi-matrix recovery and positive casework quantitation. Acceptable calibration and quality control criteria were achieved for all methods when calibrators and controls were prepared from the same urine matrix pool. Quantitative accuracy, determined by addition of analytes to multi-donor urine pools at two concentration levels, resulted in acceptable percent relative standard deviation (%RSD) and bias for TAC and ASIL-IS methods. SSIL-IS method quantitations in analyte-supplemented donor pools revealed a %RSD ranging from 20-60% for more than 30% of the analytes and a method bias that ranged up to 87%, with a differential matrix effect on analyte and shared internal standard accounting for the imprecision and bias. Analyte quantitation in 162 authentic case samples showed close agreement for TAC and ASIL-IS methods, with greater variance in the SSIL-IS method. The study demonstrates effective matrix normalization by ASIL-IS and TAC methods and a matrix-caused bias in the SSIL-IS method.

The Hidden Cost of the Opioid Epidemic in the United States: Drug Screening in Insurance Claims

BACKGROUND

The opioid crisis has had a substantial financial impact on the health care system in the United States. This study evaluates how health plans have been affected financially and shows how a laboratory benefit management (LBM) program can be used to address related drug testing in an outpatient setting.

METHODS

Monthly claims data from private health plans were collected from June 1, 2016 to February 29, 2020. The total number of claims (units) for definitive and presumptive drug testing were calculated and the number of paid claims recorded. Claims distribution by laboratory type and medical code billed, the paid rate and compound annual growth rate, and the test distribution and paid rate of rendering providers who had submitted a minimum of 1000 claims were determined.

RESULTS

In total, 2,004,230 drug testing claims were submitted. After the LBM program was implemented, the percentage of paid claims for definitive drug testing (Healthcare Common Procedure Coding System code G0483) decreased and the paid rate for the low-cost tests (HCPCS code G0480) in physician office and independent laboratory settings increased. The compound annual growth rate for G0483 claims submitted indicated a 70.5% and 31.9% decrease in payments to physician offices and independent laboratories, respectively, for the period ending February 2020.

CONCLUSIONS

An LBM program can positively address policy enforcement while reducing unnecessarily complex tests and limiting potential fraud, waste, and abuse by directing testing toward laboratories amenable to cost-efficient contractual savings. Moreover, for definitive drug testing, the enforcement of the use of Healthcare Common Procedure Coding System codes and a move toward more cost-efficient tests (G0480), when clinically applicable, supported by clinical practice guidelines, or evidence-based medicine, is an approach to providing medical benefits while maintaining health costs.