Executive Summary: American Association of Clinical Chemistry Laboratory Medicine Practice Guideline—Using Clinical Laboratory Tests to Monitor Drug Therapy in Pain Management Patients

New psychoactive Substances: A Canadian perspective on emerging trends and challenges for the clinical laboratory

The production and use of New Psychoactive Substances (NPS) has skyrocketed over the last decade, causing major challenges for government authorities, public health agencies, and laboratories across the world. NPS are designed to mimic the psychoactive effects of unregulated or controlled drugs, while constantly being modified to evade drug control regulation. Hence, they are referred to as "legal highs", as they are technically legal to sell, possess, and use. NPS can be classified by their pharmacological mechanism of action and include cannabimimetic, depressants, dissociatives, hallucinogens, opioids, and stimulants. There is significant structural diversity within each NPS class, leading to variable detection using traditional clinical laboratory testing and complicating the interpretation of results. In this article, we review each of the NPS classes and summarize their associated mechanism of action, common structures, and metabolic pathways, and provide examples of recent drugs and emerging threats with a focus on Canadian drug trends. We also explore the current analytical advantages and limitations commonly faced by the clinical laboratory and provide insight on how toxicosurveillance can improve detection of NPS in the ever-changing NPS landscape.

Assessing knowledge gaps and educational needs in urine drug test interpretation among health care professionals

OBJECTIVES

Urine drug testing (UDT) is a critical tool used in medical, forensic, and occupational settings, but interpreting results can be challenging. We performed a study to assess the ability of health care professionals to interpret UDT results accurately.

METHODS

In total, 911 clinical and laboratory professionals in the United States and Canada responded to a survey with questions gauging expertise in UDT interpretation. Responses were analyzed to identify knowledge gaps.

RESULTS

Toxicologists and laboratory PhD scientists performed well, with means of 4.82 and 4.63 questions answered correctly (out of 6 possible), respectively. Physicians specializing in pathology, emergency medicine, primary care, and internal medicine, however, displayed concerning knowledge gaps, as did laboratorians with nondoctoral degrees. Experience and training correlated with interpretation accuracy. Identification of simulated compliance as well as understanding opioid exposure, metabolism, and immunoassay cross-reactivity were among the most clinically significant knowledge gaps. More than 30% of survey respondents indicated that they would seek UDT information from the internet or peers rather than clinical or laboratory experts.

CONCLUSIONS

The study highlighted the need for targeted education and better collaboration between clinical and laboratory experts and other health care professionals to ensure that when physicians order UDT, they can accurately interpret results and reduce harm.

The 2023 Taiwan Stroke Society Guidelines for the management of patients with intracranial atherosclerotic disease

Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke, especially in Asian populations, which has a high risk of recurrent stroke and cardiovascular comorbidities. The present guidelines aim to provide updated evidence-based recommendations for diagnosis and management of patients with ICAD. Taiwan Stroke Society guideline consensus group developed recommendations for management of patients with ICAD via consensus meetings based on updated evidences. Each proposed class of recommendation and level of evidence was approved by all members of the group. The guidelines cover six topics, including (1) epidemiology and diagnostic evaluation of ICAD, (2) nonpharmacological management of ICAD, (3) medical therapy for symptomatic ICAD, (4) endovascular thrombectomy and rescue therapy for acute ischemic stroke with underlying ICAD, (5) endovascular interventional therapy for postacute symptomatic intracranial arterial stenosis, and (6) surgical treatment of chronic symptomatic intracranial arterial stenosis. Intensive medical treatment including antiplatelet therapy, risk factor control, and life style modification are essential for patients with ICAD.

Benzodiazepine analysis by an improved LC-MS/MS method illustrates usage patterns in Washington State

BACKGROUND

The standard approach for benzodiazepine detection often includes immunoassay followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The illicit use of non-prescribed benzodiazepines has been trending up nationally.

METHODS

We developed and validated an improved LC-MS/MS assay for benzodiazepine detection in urine. We expanded the testing panel by adding five drugs to the previous panel of ten. We determined the prevalence of individual benzodiazepines in our patient population. Immunoassay results were compared with LC-MS/MS to evaluate assay performance.

RESULTS

Clonazepam and alprazolam were the most common benzodiazepines present. Etizolam and flualprazolam were also prevalent in Washington State. Compared with the LC-MS/MS assay, the immunoassay had variable cross-reactivity, which explained false negative and false positive immunoassay results. The inclusion of new drugs in the LC-MS/MS panel significantly reduced the incidence of immunoassay results interpreted as falsely positive.

CONCLUSION

New illicit benzodiazepines have emerged regionally and nationally. The inclusion of novel drugs in LC-MS/MS assay was helpful in properly characterizing the epidemiology of benzodiazepine use in our patient population. This information will lead to better assay result interpretations and patient care, and our experiences provide a roadmap for other clinical laboratories looking to expand their testing menu or transition to new instrumentation.

Variation in Nevada primary care clinicians' use of urine drug testing to mitigate opioid harm

INTRODUCTION

The prescription opioid epidemic led to federal, state, and health system guidelines and policies aimed at mitigating opioid misuse, including presumptive urine drug testing (UDT). This study identifies whether a difference exists in UDT use among different primary care medical license types.

METHODS

The study used January 2017-April 2018 Nevada Medicaid pharmacy and professional claims data to examine presumptive UDTs. We examined correlations between UDTs and clinician characteristics (medical license type, urban/rural status, care setting) along with clinician-level measures of patient mix characteristics (proportions of patients with behavioral health diagnoses, early refills). Adjusted odds ratios (AORs) and predicted probabilities (PPs) from a logistic regression with a binomial distribution are reported. The analysis included 677 primary care clinicians (medical doctors [MD], physician assistants [PA], nurse practitioners [NP]).

RESULTS

Of those in the study, 85.1 % of clinicians did not order any presumptive UDTs. NPs had the highest proportion of UDT use (21.2 % of NPs), followed by PAs (20.0 % of PAs), and MDs (11.4 % of MDs). Adjusted analyses showed that being a PA or NP was associated with higher odds of UDT (PA: AOR: 3.6; 95 % CI: 3.1-4.1; NP: AOR: 2.5; 95 % CI: 2.2-2.8) compared to being an MD. PAs had the highest PP for ordering UDTs (2.1 %, 95 % CI: 0.5 %-8.4 %). Among clinicians who ordered UDTs, midlevel clinicians had higher mean and median UDT use (PA and NP mean: 24.3 % vs. MDs: 19.4 %; PA and NP median: 17.7 % vs. MDs: 12.5 %).

CONCLUSION

In Nevada Medicaid, UDTs are concentrated among 15 % of primary care clinicians who are frequently non-MDs. More research should include PAs and NPs when examining clinician variation in mitigating opioid misuse.

A preliminary study of hydrocodone and hydromorphone to oxycodone ratios for distinguishing impurities from independent opioid use

BACKGROUND

Urine drug testing (UDT) monitors prescription compliance and/or drug abuse. However, interpretation of UDT results obtained by liquid chromatography-tandem mass spectrometry (LC-MS-MS) can be complicated by the presence of drug impurities that are detected by highly sensitive methods. Hydrocodone is a drug impurity that can be found as high as 1% in oxycodone pills.

OBJECTIVES

We evaluated the frequency and concentration of hydrocodone and its metabolite, hydromorphone, in patients taking oxycodone to check if the ratio of hydrocodone or hydromorphone to oxycodone could distinguish between oxycodone only use from those consuming additional opiates.

DESIGN & METHODS

We correlated LC-MS/MS results with medication records of 319 patients with positive oxycodone results over 7 months (4/2021-11/2021).

RESULTS

Fifteen of 319 patients with positive oxycodone results were taking oxycodone only. For these 15 patients, the mean ratio of hydrocodone to oxycodone was 0.57% (range 0.05%-3.35%), and the mean ratio of hydromorphone to oxycodone was 0.81% (range 0.18-3.51%).

CONCLUSIONS

Hydrocodone and/or hydromorphone are detectable in patients taking only oxycodone and can likely be identified as an impurity if their calculated ratio to oxycodone is <1 %. Further validation of the ratios in a larger sample size is recommended.

Drug checking services as a surveillance tool for clinical laboratories: Examining trends in the unregulated fentanyl supply

OBJECTIVES

Timely assessment and understanding of drug trends is essential for clinical laboratories to effectively respond to the overdose epidemic. In this proof-of-concept study, we sought to determine whether information obtained through Toronto's Drug Checking Services (DCS) and cross-provincial urine drug testing (UDT) data can be used as a surveillance tool for clinical laboratories and discuss the value of collaboration between the clinical laboratory, clinicians, and community partners to optimize patient care.

DESIGN & METHODS

Mass spectrometry-based UDT data from LifeLabs Ontario (n = 127,529) and British Columbia (n = 14,848), and drug checking data from Toronto DCS (n = 3,308 drugs or used paraphernalia) was collected between August 2020 and October 2021. Fentanyl co-positivity with toxic adulterants such as benzodiazepine-related drugs and fentanyl analogues were examined.

RESULTS

The percent co-positivity of fentanyl with etizolam, flualprazolam, flubromazolam, carfentanil, and acetylfentanyl in both Ontario UDT and DCS drugs/used paraphernalia showed similar trends. Regional differences in co-positivity with etizolam and fentanyl analogues were noted between Ontario and British Columbia UDT with patterns consistent over the entire 15-month collection period.

CONCLUSIONS

Clinical laboratories should connect with their local DCS, if available, to understand and monitor unregulated drug trends. These data can be used as an important tool to help clinical laboratories tailor their UDT menus and thereby provide a community-focused service to improve patient care.

Urinalysis based assessment of compliance and drug use patterns in patients prescribed tramadol: A cross-sectional study from a tertiary care centre

BACKGROUND

Strict adherence to pharmacological dosage regimens is a prerequisite to the success of most treatments, particularly for patients in drug abuse programs. The compliance of tramadol, an atypical non-scheduled narcotic analgesic, using objective method has not been adequately studied in an Indian setting.

AIM

To evaluate the compliance and pattern of drug use among opioid-dependent subjects prescribed tramadol based on urinalysis.

METHOD

Fifty male opioid-dependent patients (ICD 10), seeking treatment at a tertiary de-addiction treatment centre of North India on tramadol prescription for atleast past four weeks were included. Self-reported substance use was recorded using semi-structured proforma. Ten ml of urine was collected for the assessment of compliance of tramadol of other substance use (morphine, buprenorphine, dextropropoxyphene, pentazocine, cannabis, benzodiazepines, pheniramine). All these drugs were analyzed using the immunoassay-based Cassette test and Gas Chromatography in human urine.

RESULT

Mean age of the participants was 42.8 years and the mean duration of opioid use was 15.9years. The urine specimen of all subjects tested positive for tramadol. Urinalysis revealed benzodiazepines, cannabis, and pheniramine to be the most common substances of use in this population. It was seen that agreement of self-reporting and urine test results was good for morphine (κ = 0.558) and cannabis (κ = 0.312) and was poor for buprenorphine, pentazocine, and pheniramine.

CONCLUSION

The study demonstrates the continued use of several illicit or non-prescribed medications in a medication-assisted opioid treatment population. The results affirm the reliability of urinalysis as an adjunct for testing compliance in such a population.

The North American opioid epidemic: opportunities and challenges for clinical laboratories

Since 1999, the opioid epidemic in North America has resulted in over 1 million deaths, and it continues to escalate despite numerous efforts in various arenas to combat the upward trend. Clinical laboratories provide drug testing to support practices such as emergency medicine, substance use disorder treatment, and pain management; increasingly, these laboratories are collaborating in novel partnerships including drug-checking services (DCS) and multidisciplinary treatment teams. This review examines drug testing related to management of licit and illicit opioid use, new technologies and test strategies employed by clinical laboratories, barriers hindering laboratory response to the opioid epidemic, and areas for improvement and standardization within drug testing. Literature search terms included combinations of "opioid," "opiate," "fentanyl," "laboratory," "epidemic," "crisis," "mass spectrometry," "immunoassay," "drug screen," "drug test," "guidelines," plus review of PubMed "similar articles" and references within publications. While immunoassay (IA) and point-of-care (POC) test options for synthetic opioids are increasingly available, mass spectrometry (MS) platforms offer the greatest flexibility and sensitivity for detecting novel, potent opioids. Previously reserved as a second-tier application in most drug test algorithms, MS assays are gaining a larger role in initial screening for specific patients and DCS. However, there are substantial differences among laboratories in terms of updating test menus, algorithms, and technologies to meet changing clinical needs. While some clinical laboratories lack the resources and expertise to implement MS, many are also slow to adopt available IA and POC tests for newer opioids such as fentanyl. MS-based testing also presents challenges, including gaps in available guidance for assay validation and ongoing performance assessment that contribute to a dramatic lack of standardization among laboratories. We identify opportunities for improvement in laboratory operations, reporting, and interpretation of drug test results, including laboratorian and provider education and laboratory-focused guidelines. We also highlight the need for collaboration with providers, assay and instrument manufacturers, and national organizations to increase the effectiveness of clinical laboratory and provider efforts in preventing morbidity and mortality associated with opioid use and misuse.

Impact of genetic variation in CYP2C19, CYP2D6, and CYP3A4 on oxycodone and its metabolites in a large database of clinical urine drug tests

Urine drug testing (UDT) is a tool for monitoring drug use, including oxycodone. While variation in cytochrome P450 (CYP) genes is known to alter oxycodone metabolism, its impact on UDT results of oxycodone and its metabolites has not been well-studied. Here, multivariate analysis was performed on retrospective UDT results of 90,379 specimens collected from 14,684 genotyped patients prescribed oxycodone. Genetic variation in CYP2D6 and CYP2C19 had a significant impact on oxymorphone/oxycodone ratios, with a 6.9-fold difference between CYP2D6 ultrarapid metabolizers (UMs) and poor metabolizers (PMs; p < 10^-300) and a 1.6-fold difference between CYP2C19 UMs and PMs (p = 1.50 × 10^-4). CYP2D6 variation also significantly impacted noroxycodone/oxycodone ratios (p = 6.95 × 10^-38). Oxycodone-positive specimens from CYP2D6 PMs were ~5-fold more likely to be oxymorphone-negative compared to normal metabolizers. These findings indicate that multivariate analysis of UDT data may be used to reveal the real-world impact of genetic and non-genetic factors on drug metabolism.

Liquid chromatography–tandem mass spectrometry for clinical diagnostics

Mass spectrometry is a powerful analytical tool used for the analysis of a wide range of substances and matrices; it is increasingly utilized for clinical applications in laboratory medicine. This Primer includes an overview of basic mass spectrometry concepts, focusing primarily on tandem mass spectrometry. We discuss experimental considerations and quality management, and provide an overview of some key applications in the clinic. Lastly, the Primer discusses significant challenges for implementation of mass spectrometry in clinical laboratories and provides an outlook of where there are emerging clinical applications for this technology.

Tandem mass spectrometry is increasingly utilized for clinical applications in laboratory medicine. In this Primer, Thomas et al. discuss experimental considerations and quality management for implementing clinical tandem mass spectrometry in the clinic with an overview of some key applications.

Factors Compromising Glucuronidase Performance in Urine Drug Testing Potentially Resulting in False Negatives

Next generation β-glucuronidases can effectively cleave glucuronides in urine at room temperature. However, during the discovery studies, additional challenges were identified for urine drug testing across biologically relevant pH extremes and patient urine specimens. Different enzymes were evaluated across clinical urine specimens and commercially available urine control matrices. Each enzyme shows distinct substrate preferences, pH optima, and variability across clinical specimens. These results demonstrate how reliance on a single glucuronidated substrate as the internal hydrolysis control cannot ensure performance across a broader panel of analytes. Moreover, sample specific urine properties compromise β-glucuronidases to varying levels, more pronounced for some enzymes, and thereby lower the recovery of some drug analytes in an enzyme-specific manner. A minimum of 3-fold dilution of urine with buffer yields measurable improvements in achieving target pH and reducing the impact of endogenous compounds on enzyme performance. After subjecting the enzymes to pH extremes and compromising chemicals, one particular β-glucuronidase was identified that addressed many of these challenges and greatly lower the risk of failed hydrolyses. In summary, we present strategies to evaluate glucuronidases that aid in higher accuracy urine drug tests with lower potential for false negatives.

Trends in Urine Drug Testing Among Long-term Opioid Users, 2012-2018

INTRODUCTION

Long-term opioid therapy increases the risk of opioid overdose death. Government agencies and medical societies, including the Center for Disease Control and Prevention and the American Society for Clinical Oncology, emphasized risk mitigation strategies, including urine drug testing, in published guidelines. Urine drug testing rates, time trends, and covariates among long-term opioid therapy users were examined to gauge guideline adherence.

METHODS

Using Optum's De-identified Clinformatics DataMart, an incidence cohort (n=28,790) and prevalence cohort (n=621,449) were created to measure baseline and annual urine drug testing, respectively, from 2012 to 2018. Urine drug testing time trends were evaluated by demographics, pain conditions, and Elixhauser comorbidity index. A multivariable generalized estimating model was developed in 2020 to examine the factors associated with urine drug testing.

RESULTS

Annual urine drug testing rates doubled from 25.6% in 2012 to 52.2% in 2018, whereas baseline urine drug testing also increased from 3.75% to 11.1%. Annual urine drug testing increased within each age group over time; however, older patients (OR=0.21, 95% CI=0.21, 0.22, aged >79 years) and patients with cancer (OR=0.82, 95% CI=0.80, 0.84) were less likely to receive urine drug testing. Patients residing in the South (OR=1.99, 95% CI=1.96, 2.01) and those with back pain (OR=2.04, 95% CI=2.02, 2.06) or with other chronic pain (OR=1.64, 95% CI=1.62, 1.66) were significantly more likely to be tested. Independent predictors of baseline urine drug testing were similar to predictors of annual urine drug testing.

CONCLUSIONS

Despite increasing urine drug testing trends from 2012 to 2018, annual and baseline urine drug testing remained low in 2018, relative to numerous guideline recommendations. Findings suggest a need for research on better guideline implementation strategies and the effectiveness of urine drug testing on patient outcomes.

Review of the Current State of Urine Drug Testing in Chronic Pain: Still Effective as a Clinical Tool and Curbing Abuse, or an Arcane Test?

PURPOSE OF REVIEW

Therapeutic use, misuse, abuse, and diversion of controlled substances in managing chronic non-cancer pain remain a major concern for physicians, the government, payers, and patients. The challenge remains finding effective diagnostic tools that can be clinically validated to eliminate or substantially reduce the abuse of controlled prescription drugs, while still assuring the proper treatment of those patients in pain. Urine drug testing still remains an important means of adherence monitoring, but questions arise as to its relevance and effectiveness. This review examines the role of UDT, determines its utility in current clinical practice, and investigates its relevance in current chronic pain management.

RECENT FINDINGS

A review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Literature was searched from year 2000 to present examining the relevance and role of UDT in monitoring chronic opioid therapy along with reliability and accuracy, appropriate use, overuse, misuse, and abuse. There are only a limited number of reviews and investigations on UDT, despite the fact that clinicians who prescribe controlled medications for chronic states commonly are expected to utilize UDT. Therefore, despite highly prevalent use, there is a limited publication base from which to draw in this present study. Regardless of experience or training background, physicians and healthcare providers can much more adequately assess opioid therapy with the aid of UDT, which often requires confirmatory testing by a laboratory for clinical and therapeutic prescribing decisions. It has become a strongly recommended aspect of pain care with controlled substances locally, regionally, and nationally. Incorporating UDT for all patients in whom chronic opioid therapy is undertaken is consistent with state and national guidelines and best practice strategies. Practice standards vary as to the frequency of UDT locally, regionally, and nationally, however.

Physician Perspective and Challenges Ordering/Interpreting Laboratory Tests Related to the Opioid Crisis in America

ABSTRACT

The opioid crisis is a profound public health crisis in the United States. It has significantly increased morbidity and mortality in our nation. There are many contributing factors to the opioid crisis, including a strong national and international interest to treat pain as effectively as possible. To combat this crisis, numerous strategies have been implemented over the past few years at the legislative, health system, and patient levels. As a result of these efforts, for the first time since 1999, drug overdose deaths in the United States decreased from 2017 to 2018, when deaths involving all opioids, prescription opioids, and heroin decreased by 2%, 13.5%, and 4.1%, respectively. To continue to curb the opioid crisis, it is imperative to optimize pain control through multidisciplinary and multimodal approaches and to adhere to opioid prescribing guidelines from regulatory and professional organizations to minimize risks for opioid misuse and abuse. Urine drug testing is an important means to assist with opioid monitoring and safe opioid prescribing. There are challenges when ordering urine drug tests, collecting specimens, and interpreting test results. Inaccurate interpretations of laboratory results can have significantly negative impacts on patients care and life. There is a critical need for prescriber education by laboratory experts in the use of drug testing and interpretation of results. To interpret test results correctly and make safe prescribing decisions, it is very important for prescribers/providers to consult clinical toxicologists, laboratory directors, and reporting staff. This interaction is vital and provides excellence of care for patients. This review aims to provide information concerning the opioid crisis in the United States and summarizes the challenges ordering and interpreting opioid-related laboratory testing as well as pertinent guidelines and recommendations.

Point-of-Care Drug of Abuse Testing in the Opioid Epidemic

CONTEXT.—

The United States is experiencing an opioid overdose epidemic. Point-of-care (POC) drug of abuse testing is a useful tool to combat the intensified opioid epidemic.

OBJECTIVES.—

To review commercially available POC drug of abuse testing involving opioids, to review opportunities and challenges for POC opioid testing and emerging testing methods in research literature, and finally to summarize unmet clinical needs and future development prospects.

DATA SOURCES.—

The Google search engine was used to access information for commercial opioid POC devices and the Google Scholar search engine was used to access research literature published from 2000 to 2019 for opioid POC tests.

CONCLUSIONS.—

The opioid epidemic provides unprecedented opportunities for POC drug testing, with significant clinical needs. Compared with gold standard tests, limitations for commercially available opioid POC testing include lower analytical sensitivity, lower specificity, and cross-reactivity. In response to unmet clinical needs, novel methods have emerged in research literature, such as microfluidics and miniature mass spectrometry. Future prospects include the development of quantitative POC devices and smarter and real-time drug testing.

Evaluation of Phenotypic and Genotypic Variations of Drug Metabolising Enzymes and Transporters in Chronic Pain Patients Facing Adverse Drug Reactions or Non-Response to Analgesics: A Retrospective Study

This retrospective study evaluates the link between an adverse drug reaction (ADR) or a non-response to treatment and cytochromes P450 (CYP), P-glycoprotein (P-gp) or catechol-O-methyltransferase (COMT) activity in patients taking analgesic drugs for chronic pain. Patients referred to a pain center for an ADR or a non-response to an analgesic drug between January 2005 and November 2014 were included. The genotype and/or phenotype was obtained for assessment of the CYPs, P-gp or COMT activities. The relation between the event and the result of the genotype and/or phenotype was evaluated using a semi-quantitative scale. Our analysis included 243 individual genotypic and/or phenotypic explorations. Genotypes/phenotypes were mainly assessed because of an ADR (n = 145, 59.7%), and the majority of clinical situations were observed with prodrug opioids (n = 148, 60.9%). The probability of a link between an ADR or a non-response and the genotypic/phenotypic status of the patient was evaluated as intermediate to high in 40% and 28.2% of all cases, respectively. The drugs in which the probability of an association was the strongest were the prodrug opioids, with an intermediate to high link in 45.6% of the cases for occurrence of ADRs and 36.0% of the cases for non-response. This study shows that the genotypic and phenotypic approach is useful to understand ADRs or therapeutic resistance to a usual therapeutic dosage, and can be part of the evaluation of chronic pain patients.

Provider Misinterpretation, Documentation, and Follow-Up of Definitive Urine Drug Testing Results

BACKGROUND

Urine drug testing (UDT) is an essential tool to monitor opioid misuse among patients on chronic opioid therapy. Inaccurate interpretation of UDT can have deleterious consequences. Providers' ability to accurately interpret and document UDT, particularly definitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) results, has not been widely studied.

OBJECTIVE

To examine whether providers correctly interpret, document, and communicate LC-MS/MS UDT results.

DESIGN

This is a retrospective chart review of 160 UDT results (80 aberrant; 80 non-aberrant) between August 2017 and February 2018 from 5 ambulatory clinics (3 primary care, 1 oncology, 1 pain management). Aberrant results were classified into one or more of the following categories: illicit drug use, simulated compliance, not taking prescribed medication, and taking a medication not prescribed. Accurate result interpretation was defined as concordance between the provider's documented interpretation and an expert laboratory toxicologist's interpretation. Outcome measures were concordance between provider and laboratory interpretation of UDT results, documentation of UDT results, results acknowledgement in the electronic health record, communication of results to the patient, and rate of prescription refills.

KEY RESULTS

Aberrant results were most frequently due to illicit drug use. Overall, only 88 of the 160 (55%) had any documented provider interpretations of which 25/88 (28%) were discordant with the laboratory toxicologist's interpretation. Thirty-six of the 160 (23%) documented communication of the results to the patient. Communicating results was more likely to be documented if the results were aberrant compared with non-aberrant (33/80 [41%] vs. 3/80 [4%], p < 0.001). In all cases where provider interpretations were discordant with the laboratory interpretation, prescriptions were refilled.

CONCLUSIONS

Erroneous provider interpretation of UDT results, infrequent documentation of interpretation, lack of communication of results to patients, and prescription refills despite inaccurate interpretations are common. Expert assistance with urine toxicology interpretations may be needed to improve provider accuracy when interpreting toxicology results.

The challenge that chlorine presented during the development of a benzodiazepine assay

During the routine validation of a benzodiazepine method (performed on a Liquid Chromatography - Tandem Mass Spectrometer), it was noted that lorazepam, triazolam, and α-hydroxytriazolam showed a quadratic shift/bias in the calibration curve, particularly at high concentrations. The ultimate cause of this bias was determined to be due to the natural presence of chlorine (Cl) isotopes (³⁵Cl and ³⁷Cl) in these benzodiazepines. The presence of the heavy (³⁷Cl) isoforms of Cl resulted in the analyte's mass being the same as the internal standard which, in turn, caused the internal standard to appear "falsely increased", thus skewing the calibration curve. One solution to this potential issue was to take advantage of this natural phenomenon and use the Cl heavy isoforms of the respectively labeled internal standards.

Urine is superior to oral fluid for detecting buprenorphine compliance in patients undergoing treatment for opioid addiction

BACKGROUND

Buprenorphine (BUP) is commonly used in opioid agonist medication-assisted treatment (OA-MAT). Oral fluid (OF) is an attractive option for compliance monitoring during OA-MAT as collections are observed and evidence suggests that OF is less likely to be adulterated than urine (UR). However, the clinical and analytical performance of each matrix for monitoring BUP compliance has not been well studied.

METHODS

We collected 260 paired OF and UR specimens. Concentrations of buprenorphine (BUP) and norbuprenorphine (NBUP) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in each matrix. The glucuronide metabolites and naloxone concentrations were also measured in UR by LC-MS/MS. Medications were reviewed and UR creatinine concentrations were determined.

RESULTS

147/260 specimens (57%) were positive for BUP and/or metabolites in one or both matrices. BUP and/or metabolites were more likely to be detected in UR (p < 0.001). 1 OF specimen and 12 UR specimens were considered adulterated/substituted. The majority of patients prescribed BUP were positive for BUP in UR (97%) as opposed to OF (78%). The detection of undisclosed use approximately doubled in UR.

CONCLUSIONS

UR is the preferred matrix for detecting both buprenorphine compliance and undisclosed use. Clinicians should consider the ease of collection, risk of adulteration and detection of illicit drug use when deciding on an appropriate matrix. If OF testing is clinically necessary, UR should be measured in conjunction with OF at least periodically to avoid false negative BUP results.

Dilution of Urine Followed by Adulteration in an Attempt to Deceive the Laboratory

Adulteration of samples submitted for toxicological analyses can present unique challenges to non-forensic clinical laboratories. With the number of overdose-related deaths expected to surpass 60,000 in 2018, it is incumbent on all members of the healthcare team to be active participants in curbing opioid dependence and identifying prescription drug misuse and diversion. Recently published guidelines have sought to provide guidance to laboratories overseeing prescription drug-monitoring programs. We present a case of sample adulteration in an attempt to conceal prescription non-compliance. The patient possessed only an active prescription for hydrocodone but on initial antibody-based screening the sample tested positive for benzodiazepines and oxycodone in addition to opiates. Active communication between the pain management clinic and the clinical laboratory alerted staff to conduct a more thorough investigation including sample validity testing, analyses of paired serum specimens by liquid chromatography tandem mass spectrometry. Analyses revealed the patient submitted a dilute urine specimen with a crushed hydrocodone pill inside in an attempt to hide prescription non-compliance. Previous screenings had been consistent with the medication list raising the question of whether this was an isolated incident or the patient had simply been more successful in manipulating specimens in the past. This case highlights the need for good communication among all members of the healthcare team and the widespread implementation of specimen validity testing for any laboratory that receives samples from pain clinics.