A web application to support the coordination of reflexive, interpretative toxicology testing

Background

Reflexive laboratory testing workflows can improve the assessment of patients receiving pain medications chronically, but complex workflows requiring pathologist input and interpretation may not be well-supported by traditional laboratory information systems. In this work, we describe the development of a web application that improves the efficiency of pathologists and laboratory staff in delivering actionable toxicology results.

Method

Before designing the application, we set out to understand the entire workflow including the laboratory workflow and pathologist review. Additionally, we gathered requirements and specifications from stakeholders. Finally, to assess the performance of the implementation of the application, we surveyed stakeholders and documented the approximate amount of time that is required in each step of the workflow.

Results

A web-based application was chosen for the ease of access for users. Relevant clinical data was routinely received and displayed in the application. The workflows in the laboratory and during the interpretation process served as the basis of the user interface. With the addition of auto-filing software, the return on investment was significant. The laboratory saved the equivalent of one full-time employee in time by automating file management and result entry.

Discussion

Implementation of a purpose-built application to support reflex and interpretation workflows in a clinical pathology practice has led to a significant improvement in laboratory efficiency. Custom- and purpose-built applications can help reduce staff burnout, reduce transcription errors, and allow staff to focus on more critical issues around quality.

Developments in high-resolution mass spectrometric analyses of new psychoactive substances

The proliferation of new psychoactive substances (NPS) has necessitated the development and improvement of current practices for the detection and identification of known NPS and newly emerging derivatives. High-resolution mass spectrometry (HRMS) is quickly becoming the industry standard for these analyses due to its ability to be operated in data-independent acquisition (DIA) modes, allowing for the collection of large amounts of data and enabling retrospective data interrogation as new information becomes available. The increasing popularity of HRMS has also prompted the exploration of new ways to screen for NPS, including broad-spectrum wastewater analysis to identify usage trends in the community and metabolomic-based approaches to examine the effects of drugs of abuse on endogenous compounds. In this paper, the novel applications of HRMS techniques to the analysis of NPS is reviewed. In particular, the development of innovative data analysis and interpretation approaches is discussed, including the application of machine learning and molecular networking to toxicological analyses.

Listening to your mass spectrometer: An open-source toolkit to visualize mass spectrometer data

Introduction

We have developed a set of tools built with open-source software that includes both a database and a visualization component to collect LC-MS/MS data and monitor quality control parameters.

Description of tool

To display LC-MS/MS data we built a parsing tool using Python and standard libraries to parse the XML files after each clinical run. The tool parses the necessary information to store a database comprised of three distinct tables. Another component to this toolkit is an interactive data visualization tool that uses the data from the database. There are 5 different visualizations that present the data based on interchangeable parameters.

Evaluation of tool

Using histogram visualization, we assessed how quality control parameters that feed our quality control algorithm, SMACK, which assists to improve the efficiency of data review and results, performed against the collective data. Using the newly identified QC parameter values from the toolkit, we compared the output of the SMACK algorithm; the number of QC flags changed in that there was a 1.7% (31/1944 observations) increase in flags and a 7.1% (138/1944 observations) decrease in presumed false positive flags, increasing the overall performance of SMACK which helped staff focus their time on reviewing more concerning QC failures.

Discussion

We have developed a customizable web-based dashboard for instrument performance monitoring for our opiate confirmation LC-MS/MS assay using data collected with each batch. The web-based platform allows users to monitor instrument performance and can encompass other instruments throughout the laboratory. This information can help the laboratory take proactive measures to maintain instruments, ultimately reducing the amount down time needed for maintenance.

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.

The Quantification of Oxycodone and its Phase I and II Metabolites in Urine

The purpose of this research was to develop and validate an analytical method for the detection and quantification of noroxymorphone-3β-D-glucuronide (NOMG), oxymorphone-3β-D-glucuronide (NOMG), noroxymorphone (NOM), oxymorphone (OM), 6α-oxycodol (αOCL), 6β-oxycodol (βOCL), noroxycodone (NOC) and oxycodone (OC) in urine by liquid chromatography tandem mass spectrometry to be used in a human study. The method was validated according to the Academy Standards Board Standard Practices for Method Development in Forensic Toxicology. The method was then applied to a single-dose pilot study of a subject. Urine samples were collected from the subject after ingesting 10-mg OC as an immediate-release tablet. Additionally, urine specimens (n = 15) that had previously been confirmed positive for OC were analyzed using the validated method. The calibration range for NOMG and OMG was 0.05–10 μg/mL; for all other analytes, it was 0.015–10 μg/mL. Validation parameters such as bias, precision, carryover and dilution integrity, all met the validation criteria. After the method was validated, urine samples from the first subject in the controlled dose study were analyzed. It was observed that OC, NOC and OMG contained the highest concentrations and were present in either the 0.5 or 1 h void. NOC and OMG were detected until the 48 h collection, while OC was detectable till the 24 h collection. Time to reach maximum concentration (T_max) in the urine was achieved within 1.5 h for OC and within 3 h for NOC and OMG. Maximum concentration (C_max) in the urine for OC, NOC and OMG was 3.15, 2.0 and 1.56 μg/mg, respectively. OC concentrations in authentic urines ranged from 0.015 to 12 μg/mL. Ranges for NOMG and OMG were 0.054–9.7 μg/mL and 0.14–67 μg/mL, respectively. A comprehensive method for the quantification of NOMG, OMG, NOM, OM, αOCL, βOCL, NOC and OC in urine was optimized and met the validation criteria. The concentrations of NOMG and OMG presented in this study provide the details needed in the forensic community to better comprehend OC pharmacokinetics.

LC-MS-sMRM method development and validation of different classes of pain panel drugs and analysis of clinical urine samples

Urine drug testing (UDT) is an important analytical/bio-analytical technique that has inevitably become an integral and vital part of a testing programme for diagnostic purposes. This manuscript presents a tailor-made LC-MS/MS quantitative assay method development and validation for a custom group of 33 pain panel drugs and their metabolites belonging to different classes (opiates, opioids, benzodiazepines, illicit, amphetamines, etc.) that are prescribed in pain management and depressant therapies. The LC-MS/MS method incorporates two experiments to enhance the sensitivity of the assay and has a run time of about 7 minutes with no prior purification of the samples required and a flow rate of 0.7 mL/min. The method also includes the second-stage metabolites for some drugs that belong to different classes but have first-stage similar metabolic pathways that will enable to correctly identify the right drug or to flag the drug that might be due to specimen tampering. Some real case examples and difficulties in peak picking were provided with some of the analytes in subject samples. Finally, the method was deliberated with some randomly selected de-identified clinical subject samples, and the data evaluated from "direct dilute and shoot analysis" and after "glucuronide hydrolysis" were compared. This method is now used to run routinely more than 100 clinical subject samples on a daily basis.

Comparative Analysis of ELISA Immunoassay and LC-QTOF for Opiate Screening

A comparative analysis of enzyme-linked immunosorbent assay (ELISA) and quadrupole time-of-flight mass spectrometry (LC-QTOF) for the detection of opioids in blood samples is presented. The Orange County Crime Lab (OCCL) was concerned that the opioid drug class was not accurately detected at low concentrations due to the use of LC-QTOF as a non-targeted screening method for multiple classes of drugs. In order to investigate this issue, 968 ante-mortem and postmortem blood samples were analyzed by ELISA for the presence of the following opioids: morphine, morphine-glucuronide, codeine, codeine-glucuronide, hydrocodone, hydromorphone, hydromorphone-glucuronide, oxycodone, oxymorphone and oxymorphone-glucuronide. All samples had been previously analyzed by LC-QTOF. Overall, 84 samples tested positive for opioids. Discrepant samples between ELISA and LC-QTOF were analyzed by a liquid chromatography tandem mass spectrometry confirmation method in order to determine the true composition of the sample. Upon review of the discrepant samples, no forensically relevant concentration of opioids was missed by LC-QTOF. Thus, the ability of the OCCL's LC-QTOF screening method was verified to detect opioids at low concentrations.

MASS SPECTROMETRY ANALYSIS OF DRUGS OF ABUSE: CHALLENGES AND EMERGING STRATEGIES

Mass spectrometry has been the "gold standard" for drugs of abuse (DoA) analysis for many decades because of the selectivity and sensitivity it affords. Recent progress in all aspects of mass spectrometry has seen significant developments in the field of DoA analysis. Mass spectrometry is particularly well suited to address the rapidly proliferating number of very high potency, novel psychoactive substances that are causing an alarming number of fatalities worldwide. This review surveys advancements in the areas of sample preparation, gas and liquid chromatography-mass spectrometry, as well as the rapidly emerging field of ambient ionization mass spectrometry. We have predominantly targeted literature progress over the past ten years and present our outlook for the future. © 2020 Periodicals, Inc. Mass Spec Rev.

A Rapid Dilute-and-Shoot UPLC-MS/MS Assay to Simultaneously Measure 37 Drugs and Related Metabolites in Human Urine for Use in Clinical Pain Management

Background

Monitoring of medication compliance and drug abuse is used by clinicians to increase patient prescription drug compliance and reduce illicit drug abuse and diversion. Despite available immunoassays, chromatography-mass spectrometry–based methods are considered the gold standard for urine drug monitoring owing to higher sensitivities and specificities. Herein, we report a fast, convenient ultraperformance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) assay to detect or quantify 37 clinically relevant prescription drugs, drugs of abuse, and related glucuronides and other metabolites in human urine by single diluted sample injection.

Methods

Analytes consisted of prescription and illicit opioids, benzodiazepines, and drugs of abuse, including parent compounds and glucuronidated and nonglucuronidated metabolites. Urine samples were diluted with water and supplemented with deuterated internal standards without enzymatic hydrolysis, analyte extraction, or sample purification. Analytes were separated by reversed-phase UPLC and quantified by positive-mode electrospray ionization and collision-induced dissociation MS. Assay validation followed Food and Drug Administration bioanalytical guidelines.

Results

Total analytical run time was 5.5 min. All analytes demonstrated acceptable inter- and intraassay accuracy, imprecision, and linearity throughout clinically relevant analytical ranges (1–2000 ng/mL, depending on analyte). All analytes demonstrated acceptable selectivity, stability, matrix effects, carryover, and performance compared to national reference laboratory or previously validated in-house methods. A total of 23 and 14 analytes were validated for quantitative and qualitative testing, respectively.

Conclusions

A convenient UPLC-MS/MS assay for simultaneously monitoring 37 analytes in human urine was validated for use in pain management testing. Advantages of this multiplex assay include facile sample preparation and higher-throughput definitive detection including glucuronide metabolite quantification.

Cannabis Legalization Does Not Influence Patient Compliance with Opioid Therapy

BACKGROUND

Prescription opioid use and opioid related deaths continue to increase nationwide. Several states have adopted legislation allowing for recreational use of cannabis. Little is known about how recreational cannabis laws impact compliance in chronic pain patients who have been prescribed opioid therapy. The goals of this study were to (1) retrospectively assess the effect of cannabis use on compliance with opioid therapy in a high-risk patient population and (2) determine the impact of legalization of recreational cannabis on patients prescribed therapeutic opioids.

METHODS

We conducted a retrospective cohort study on results from a "high-risk" urine drug testing panel. Results from 1 year before and 1 year after initiation of recreational cannabis legislation were analyzed. This testing panel included qualitative assays for cannabinoids and 9 other common drugs of abuse in addition to a quantitative LC-MS/MS assay for 23 different opioids and metabolites. Opioid compliance was assigned by reviewing pathologists' interpretations.

RESULTS

In the pre-legalization period, 1776 panels were performed, and in the post-legalization, 1648 panels were performed. An increase (6%) in the rate of positive cannabinoids screening results was observed after legalization of recreational cannabis; however, the overall compliance rate was consistent.

CONCLUSIONS

The results of this study suggest that legalization of recreational cannabis does not affect compliance rate in patients treated with opioid therapy for chronic pain.

Rational Urine Drug Monitoring in Patients Receiving Opioids for Chronic Pain: Consensus Recommendations

Objective

To develop consensus recommendations on urine drug monitoring (UDM) in patients with chronic pain who are prescribed opioids.

Methods

An interdisciplinary group of clinicians with expertise in pain, substance use disorders, and primary care conducted virtual meetings to review relevant literature and existing guidelines and share their clinical experience in UDM before reaching consensus recommendations.

Results

Definitive (e.g., chromatography-based) testing is recommended as most clinically appropriate for UDM because of its accuracy; however, institutional or payer policies may require initial use of presumptive testing (i.e., immunoassay). The rational choice of substances to analyze for UDM involves considerations that are specific to each patient and related to illicit drug availability. Appropriate opioid risk stratification is based on patient history (especially psychiatric conditions or history of opioid or substance use disorder), prescription drug monitoring program data, results from validated risk assessment tools, and previous UDM. Urine drug monitoring is suggested to be performed at baseline for most patients prescribed opioids for chronic pain and at least annually for those at low risk, two or more times per year for those at moderate risk, and three or more times per year for those at high risk. Additional UDM should be performed as needed on the basis of clinical judgment.

Conclusions

Although evidence on the efficacy of UDM in preventing opioid use disorder, overdose, and diversion is limited, UDM is recommended by the panel as part of ongoing comprehensive risk monitoring in patients prescribed opioids for chronic pain.

Harmonization of blood-based indicators of iron status: making the hard work matter

Blood-based indicators that are used in the assessment of iron status are assumed to be accurate. In practice, inaccuracies in these measurements exist and stem from bias and variability. For example, the analytic variability of serum ferritin measurements across laboratories is very high (>15%), which increases the rate of misclassification in clinical and epidemiologic studies. The procedures that are used in laboratory medicine to minimize bias and variability could be used effectively in clinical research studies, particularly in the evaluation of iron deficiency and its associated anemia in pregnancy and early childhood and in characterizing states of iron repletion and excess. The harmonization and standardization of traditional and novel bioindicators of iron status will allow results from clinical studies to be more meaningfully translated into clinical practice by providing a firm foundation for clinical laboratories to set appropriate cutoffs. In addition, proficiency testing monitors the performance of the methods over time. It is important that measures of iron status be evaluated, validated, and performed in a manner that is consistent with standard procedures in laboratory medicine.

Prescription Opioids. VI. Metabolism and Excretion of Hydromorphone in Urine Following Controlled Single-Dose Administration

Hydromorphone (HM), a prescription opioid and metabolite of morphine and hydrocodone, has been included in proposed revisions to the Mandatory Guidelines for Federal Workplace Drug Testing Programs. This study characterized the time course of HM in hydrolyzed and non-hydrolyzed urine specimens. Twelve healthy subjects were administered a single 8 mg controlled-release HM dose, followed by periodic collection of pooled urine specimens for 54 h following administration. Analysis of total and free HM was conducted by liquid chromatography tandem mass spectrometry at a 50 ng/mL limit of quantitation. Detection periods were determined over a range of thresholds from 50 to 2,000 ng/mL. HM was detected in 85.3% and 47.6% of hydrolyzed and non-hydrolyzed post-dose specimens, respectively. Initial detection of total HM was frequently observed in the first 4-6 h following dosing. The period of detection at the 50 ng/mL threshold averaged 52.3 h for total HM and 38.0 h for free HM. These data support that HM detection is optimized by using low thresholds (50-100 ng/mL) and including conjugated HM in the analysis.

Prescription Opioids. V. Metabolism and Excretion of Oxymorphone in Urine Following Controlled Single Dose Administration

Oxymorphone (OM), a prescription opioid and metabolite of oxycodone, was included in the recently published proposed revisions to the Mandatory Guidelines for Federal Workplace Drug Testing Programs. To facilitate toxicological interpretation, this study characterized the time course of OM and its metabolite, noroxymorphone (NOM), in hydrolyzed and non-hydrolyzed urine specimens. Twelve healthy subjects were administered a single 10 mg controlled-release OM dose, followed by a periodic collection of pooled urine specimens for 54 h following administration. Analysis for free and total OM and NOM was conducted by liquid chromatography tandem mass spectrometry (LC-MS-MS), at a 50 ng/mL limit of quantitation (LOQ). Following enzymatic hydrolysis, OM and NOM were detected in 89.9% and 13.5% specimens, respectively. Without hydrolysis, OM was detected in 8.1% specimens, and NOM was not detected. The mean ratio of hydrolyzed OM to NOM was 41.6. OM was frequently detected in the first pooled collection 0-2 h post-dose, appearing at a mean of 2.4 h. NOM appeared at a mean of 8.3 h. The period of detection at the 50 ng/mL threshold averaged 50.7 h for OM and 11.0 h for NOM. These data support that OM analysis conducted using a 50 ng/mL threshold should include hydrolysis or optimize sensitivity for conjugated OM.

Applications and challenges in using LC–MS/MS assays for quantitative doping analysis

LC–MS/MS is useful for qualitative and quantitative analysis of ‘doped’ biological samples from athletes. LC–MS/MS-based assays at low-mass resolution allow fast and sensitive screening and quantification of targeted analytes that are based on preselected diagnostic precursor–product ion pairs. Whereas LC coupled with high-resolution/high-accuracy MS can be used for identification and quantification, both have advantages and challenges for routine analysis. Here, we review the literature regarding various quantification methods for measuring prohibited substances in athletes as they pertain to World Anti-Doping Agency regulations.

Use of psychotropic drug urine test strips in opiate maintenance therapy: A clinical assessment of its advantages

BACKGROUND

Methadone and buprenorphine are the 2 opiate maintenance treatments (OMTs) available in France. According to good clinical practices, a full clinical and biological assessment is required before deciding to initiate or renew an OMT. For methadone, this assessment includes psychoactive drug consumption investigation through an initial interview completed by a systematic urine test mandatory before starting methadone treatment. In case of buprenorphine prescription, the situation is less clear and the urine test was not systematically performed. This work aims at evaluating changes in the therapeutic strategy brought by the systematic use of urine strips for detecting drug consumptions.

METHODS

During 1 month, for each case of OMT renewal, physicians belonging to the 3 types of prescribing structures in France (general medicine, specialized centers for drug addict patients, and specialized centers for drug addict patients in prison) had to complete a specific questionnaire about prescription renewal. This questionnaire contained 2 parts. The first part was completed by the physicians before the urine test strip realization. The second part was completed by the same physicians at the end of the consultation, after obtaining the results from the urine test strip. A change between parts 1 and 2 of the questionnaire concerning OMT prescription, dialogue with the patient, associated psychotropic drug prescription, and orientation were considered as a change in therapeutic strategy.

RESULTS

A total of 429 questionnaires have been collected. Among them, 315 showed at least 1 change in therapeutic strategy (73.4%).

CONCLUSIONS

This study highlighted the important benefits brought by the urine test strip in managing patients under opiate maintenance treatment. Urine test strips provided an immediate answer that allowed physicians to optimize their therapeutic strategy. However, regulatory evolutions would be necessary to ease their implantation.

Profiles of Urine Drug Test in Clinical Pain Patients vs Pain Research Study Subjects

OBJECTIVE

To examine similarities and differences in urine drug test (UDT) results in clinical pain patients and pain subjects participating in pain research studies.

DESIGN

An observational study with retrospective chart review and data analysis.

METHODS

We analyzed 1,874 UDT results obtained from 1) clinical pain patients (Clinical Group; n = 1,529) and 2) pain subjects consented to participate in pain research studies (Research Group; n = 345). Since several medications such as opioids used in pain management are drugs of abuse (DOA) and can result in a positive UDT, we specifically identified those cases of positive UDT due to nonprescribed DOA and designated these cases as positive UDT with DOA (PUD).

RESULTS

We found that 1) there was a higher rate of PUD in clinical pain patients (41.3%) than in pain research study subjects (14.8%); 2) although subjects in the Research Group were informed ahead of time that UDT will be conducted as a screening test, a substantial number (14.8%) of pain research study subjects still showed PUD; 3) there were different types of DOA between clinical pain patients (cannabinoids as the top DOA) and research study subjects (cocaine as the top DOA); and 4) a common factor associated with PUD was opioid therapy in both Clinical Group and Research Group.

CONCLUSION

These results support previous findings that PUD is a common finding in clinical pain patients, particularly in those prescribed opioid therapy, and we suggest that UDT be used as routine screening testing in pain research studies.

The development of a high-performance liquid chromatography-tandem mass spectrometric method for simultaneous quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine in serum

OBJECTIVES

Development and validation of a selective, robust high-performance liquid chromatography-tandem mass spectrometric (HPLC/MS-MS) method for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine in human serum.

DESIGN AND METHODS

Drug-free human serum samples spiked with morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine were prepared by protein precipitation using methanol containing the internal standards. Samples were injected onto a Thermo Scientific AccuCore PFP column for chromatographic separation. Detection was achieved using a Thermo Scientific TSQ Vantage mass spectrometer. Assay validation followed the new Clinical and Laboratory Standards Institute (CLSI) C62-A guidelines.

RESULTS

The analytical measuring range for all analytes was determined to be 5 to 1000 ng/mL. Intra- and inter-assay precision for three quality control levels were ≤ 7.0% and ≤ 13.5%, respectively. Carryover, stability, linearity, matrix effects, extraction and processing efficiency and method comparison characteristics were acceptable relative to the CLSI C62 guidelines.

CONCLUSION

The validation of this HPLC-MS/MS method demonstrated a robust and rapid assay for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Future applications of high-resolution MS to meet the demands for pain management drug testing

Urine specimens submitted for pain management drug testing often contain multiple psychotherapeutic drugs, in addition to opioids. Immunoassay-based screen-and-confirm approaches typically used for clinical drug testing have limited sensitivity to detect therapeutic concentrations of many drugs prescribed in pain management and do not differentiate between drugs in the same class. In addition, screening for all the various illicit and prescription drugs that may be present in the pain management population requires as many as 10–20 individual immunoassays. High-resolution MS approaches have the potential to transform the way clinical drug testing is performed for pain management.

The challenges of LC–MS/MS analysis of opiates and opioids in urine

Opioids are some of the most commonly prescribed and abused drugs around the world. Primarily used for anesthesia or pain management, other opioids can also be used in the treatment of opioid addiction. Given these facts, clinicians often randomly test or monitor their patients to determine compliance or abstinence from these drugs via immunoassay methods. When a positive screen is obtained, a confirmatory assay is carried out and although the gold standard has been GC–MS, LC–MS/MS is fast becoming a valid and popular alternative. This review will discuss opioids, the complex metabolic pathways, the measurement of these drugs, the challenges involved and, finally, will describe some LC–MS/MS methods published from 2003 until 2013.