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

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

A Review of Drug Abuse, Misuse, and Related Laboratory Challenges

Various definitions can be considered for drugs and substance abuse. According to the National Institute on Abuse, the use of an over-the-counter drug in a different way than that prescribed to experience or arouse emotion is a simple form of drug abuse. The World Health Organization (WHO) also defines drug abuse as the persistent or sporadic use of drugs that are incompatible or unrelated to acceptable medical practice. With the increasing non-therapeutic use of prescription drugs, serious related consequences have also increased. Therefore, there is a need to know more precisely about the types of substances and drug abuse, which is the most important part of diagnosis and recognizing the tests that cause false positive and negative results. The purpose of this review article is to collect and summarize the most important and more common types of drugs of abuse and review the drugs that cause false results in screening tests. In addition, the most common detection methods of the drug will be reviewed and the advantages and drawbacks of each method will be discussed. In this article, we aimed to point out all the facts about the emerging problems in drug abuse, the methods of screening, and the possible false results in addition to troubleshooting strategies.

Relapses in Illicit Drug Use Among Probationers: Results in a Risk Group of Public Health Services in Bavaria

Objective: We aimed to identify in this study time trends of relapses in the illicit consumption of narcotics in a special at-risk population of former drug users under a public health perspective. Methods: In a pooled dataset of 14 consecutive calendar years (2006-2019), the use of seven different narcotic substances was studied in 380 persons with a total of 2,928 urine samples which were analyzed using a valid marker system for narcotic residues. Results: During the entire observation period, the relapse rate for cannabinoids and opiates was the highest despite abstinence requirements. It was noticeable that the relapses across all narcotics groups occurred primarily during the first 3 years of the probation period (90%) with a decrease in illegal consumption during the following years of the observation period. Conclusion: Special attention should be paid to probationers at the beginning of the probation period to develop more effective prevention strategies for substance abstinence by all involved actors in public health services.

Advances in testing for sample manipulation in clinical and forensic toxicology - Part A: urine samples

In many countries, adherence testing is used to monitor consumption behavior or to prove abstinence. Urine and hair are most commonly used, although other biological fluids are available. Positive test results are usually associated with serious legal or economic consequences. Therefore, various sample manipulation and adulteration strategies are used to circumvent such a positive result. In these critical review articles on sample adulteration of urine (part A) and hair samples (part B) in the context of clinical and forensic toxicology, recent trends and strategies to improve sample adulteration and manipulation testing published in the past 10 years are described and discussed. Typical manipulation and adulteration strategies include undercutting the limits of detection/cut-off by dilution, substitution, and adulteration. New or alternative strategies for detecting sample manipulation attempts can be generally divided into improved detection of established urine validity markers and direct and indirect techniques or approaches to screening for new adulteration markers. In this part A of the review article, we focused on urine samples, where the focus in recent years has been on new (in)direct substitution markers, particularly for synthetic (fake) urine. Despite various and promising advances in detecting manipulation, it remains a challenge in clinical and forensic toxicology, and simple, reliable, specific, and objective markers/techniques are still lacking, for example, for synthetic urine.

Impact of cannabis use on outcomes of patients admitted to an involuntary psychiatric unit: A retrospective cohort study

INTRODUCTION

Cannabis is associated with an increased risk of mental disorders, including the onset or adverse evolution of schizophrenia, bipolar disorder and depression. The aim of our study was to examine how cannabis use influences length of stay and readmissions in a unit of involuntary care.

METHOD

All patients admitted to one secure adult psychiatry unit in France in 2016 were included (n = 370). Patients were assigned to one of two groups according to detection of urinary tetrahydrocannabinol (THC + or -). Clinical outcomes, such as length of stay and readmissions, were compared between the groups in multivariate analyses.

RESULTS

We identified 130 THC + patients and 240 THC- patients. THC + patients were often young men. In adjusted analyses, THC + status was significantly associated with one-year readmissions (OR = 2.29, p = .0082) and more prescriptions of benzodiazepines (OR = 1.93, p = .02), but not antipsychotics, at discharge.

CONCLUSIONS

Cannabis users seem to have a particular profile in secure units, and are associated with specific diagnoses and treatments, and a higher risk of readmissions. Adapted management strategies might be warranted for these patients.

Urine drug-testing tampering approaches: Turkish probationers

The growing numbers of individual and social problems associated with drug abuse necessitate new approaches in drug-testing systems. Equally, drug abusers may attempt to invalidate drug testing using different methods such as adulteration, dilution and substitution. This study aims to investigate tampering methods commonly used by Turkish substance-using probationers and evaluate their effects on toxicological drug-testing results. Initially, probationer urinary screening test results and laboratory substitution documents were evaluated to investigate the dilution and substitution attempt. Additionally, an experimental study was carried out by using readily available household products (bleach, vinegar, drain opener, eye drops) for adulteration. The effect of these agents was investigated for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), amphetamine and 3,4-methylenedioxymethamphetamine (MDMA). It was determined that probationers preferred unbranded products (syringes, nylon bottles, etc.) for urine substitution. To detect dilution, screening test results were evaluated along with creatinine values. The variability of mean creatinine values can change the rate of the before-negative and after-positive ratio. For adulteration method, the high amounts of bleach provided false-negative results for THC-COOH and amphetamine, but spiking in any concentration of bleach affected MDMA results, causing a slight increase. Vinegar did not affect the THC-COOH and amphetamine results. However, false-negative results were observed for MDMA, with high amounts of vinegar-spiked urine samples. Drain opener was added in large quantities, and false-negative results were observed for all analytes. Visine eye drops did not have any effect on THC-COOH or amphetamine, but a high quantity of eye drops had a slight decreasing effect for MDMA.

What the lab can and cannot do: clinical interpretation of drug testing results

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Comparison of several immunoassays used in drugs of abuse screening: Assessment against gold standard methods and calculation of measurement uncertainty

BACKGROUND

Immunoassays provide simple, powerful and inexpensive screening methods for urine drug screening. Other substances and/or factors may interfere with the test and cause false or positive results. It is essential to understand the differences between methods to be able to evaluate their impact on the results. All evaluated immunoassays were assessed in comparison with GC-MS or LC-MS/MS, which are generally accepted as vigorous confirmation gold standard techniques.

METHODS

CEDIA, DRI, EIA and EMIT II Plus screening immunoassays were evaluated on Beckman-Coulter AU5810 analyser. All results were confirmed using GC-MS or LC-MS/MS methods. Measurement Uncertainty for immunoassays was calculated by using standard deviation multiplied by 1.96 to cover 95% confidence interval of tested samples.

RESULTS

No discrepancy was found between CEDIA and EMIT II Plus for cocaine, methadone, heroin, and benzodiazepines assays. No discrepancy was found between oxycodone DRI assay and Immunalysis enzyme immunoassay (EIA). Cannabinoids EMIT II Plus assay performed better than DRI assay. EMIT II Plus assays for amphetamine and ecstasy performed better than CEDIA amphetamine/ecstasy combined assay. Opiates EMIT II Plus assay performed better than CEDIA assay. Fentanyl Ark EIA method performed slightly better than the DRI method. Buprenorphine CEDIA second-generation assay performed better than CEDIA first-generation assay, EMIT II Plus assay and EMIT II Plus with added Beta-Glucuronidase assay. Measurement Uncertainty for immunoassays was calculated and tabulated.

CONCLUSIONS

This study covered a fundamental gap in available knowledge by evaluating the performance of screening the current new generation of immunoassays methods for drugs of abuse in urine against gold standard methods.

Metabolomic Strategies in Biomarker Research-New Approach for Indirect Identification of Drug Consumption and Sample Manipulation in Clinical and Forensic Toxicology?

Drug of abuse (DOA) consumption is a growing problem worldwide, particularly with increasing numbers of new psychoactive substances (NPS) entering the drug market. Generally, little information on their adverse effects and toxicity are available. The direct detection and identification of NPS is an analytical challenge due to their ephemerality on the drug scene. An approach that does not directly focus on the structural detection of an analyte or its metabolites, would be beneficial for this complex analytical scenario and the development of alternative screening methods could help to provide fast response on suspected NPS consumption. A metabolomics approach might represent such an alternative strategy for the identification of biomarkers for different questions in DOA testing. Metabolomics is the monitoring of changes in small (endogenous) molecules (<1,000 Da) in response to a certain stimulus, e.g., DOA consumption. For this review, a literature search targeting "metabolomics" and different DOAs or NPS was conducted. Thereby, different applications of metabolomic strategies in biomarker research for DOA identification were identified: (a) as an additional tool for metabolism studies bearing the major advantage that particularly a priori unknown or unexpected metabolites can be identified; and (b) for identification of endogenous biomarker or metabolite patterns, e.g., for synthetic cannabinoids or also to indirectly detect urine manipulation attempts by chemical adulteration or replacement with artificial urine samples. The majority of the currently available literature in that field, however, deals with metabolomic studies for DOAs to better assess their acute or chronic effects or to find biomarkers for drug addiction and tolerance. Certain changes in endogenous compounds are detected for all studied DOAs, but often similar compounds/pathways are influenced. When evaluating these studies with regard to possible biomarkers for drug consumption, the observed changes appear, albeit statistically significant, too small to reliably work as biomarker for drug consumption. Further, different drugs were shown to affect the same pathways. In conclusion, metabolomic approaches possess potential for detection of biomarkers indicating drug consumption. More studies, including more sensitive targeted analyses, multi-variant statistical models or deep-learning approaches are needed to fully explore the potential of omics science in DOA testing.

Evaluation of endogenous urinary biomarkers for indirect detection of urine adulteration attempts by five different chemical adulterants in mass spectrometry methods

Reliable detection of urine adulteration attempts to circumvent positive drug testing represents a critical step for laboratories in abstinence control settings. An ideal workflow for high-throughput testing would involve simultaneous detection of adulteration attempts in the same run with drug detection. Monitoring of degraded or oxidized endogenous urinary compounds as indirect markers has been previously evaluated for that purpose exemplified for the adulterant potassium nitrite (KNO₂ ). Fifteen, previously identified endogenous markers should now be evaluated for their general applicability to detect adulteration attempts for the adulterants hypochlorite-based bleach (NaOCl), peroxidase and peroxide (H₂ O₂ ), pyridinium chlorochromate (PCC), and iodine (I₂ ). Initial experiments revealed similar results for the tested adulterants regarding degradation of indolylacryloylglycine (IAG), uric acid (UA), or UA derivatives. 5-Hydroxyisourate (HIU), the oxidation product of UA, was however only formed by KNO₂ , PCC, and H₂ O₂ . Amino acids showed larger adulterant-dependent differences. All reactions were shown to be influenced by the adulterant concentration and the urinary pH with large variances depending on compound and adulterant. Except for HIU/PCC, all markers were stable within +/- 30% variation for all adulterants at -20°C. Receiver operating characteristics indicated best sensitivity and specificity over all adulterants for IAG (specificity 0.9, sensitivity 1.0) and UA (specificity 1.0, sensitivity 0.9). HIU gave best results for KNO₂ , PCC, and H₂ O₂ and N-acetylneuraminic acid for PCC and H₂ O₂ , respectively. When integrating a limited number of targets into existing screening methods, monitoring of UA, IAG, N-acetylneuraminic acid, and HIU is recommended.