Measurement of benzodiazepines in urine by liquid chromatography-tandem mass spectrometry: confirmation of samples screened by immunoassay

Despite the improved clinical sensitivity of the Roche benzodiazepines II assay it cannot replace mass spectrometry in all patient populations

Introduction

Benzodiazepines are frequently prescribed and misused therefore urine drug screening (UDS) is performed in many patient populations. Most current benzodiazepine immunoassays have poor sensitivity, particularly for detecting the metabolites of newer benzodiazepines such as lorazepam in urine.

Objectives

We aimed to verify the clinical performance of the new qualitative Roche Benzodiazepines II (BNZ2) immunoassay, as well as compare its performance to the Roche Benzodiazepines Plus (BENZ) assay in two patient populations: UDS in the emergency department (ED) and compliance monitoring.

Methods

An initial verification study was performed, selecting for samples containing clonazepam and lorazepam metabolites. Performance of the BNZ2 and BENZ assays was compared to liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the reference method. Sensitivity, specificity, false positive rate (FPR) and false negative rate (FNR) were determined.

Results

We verified the performance claims in the initial verification and demonstrated similar precision, with coefficient of variations (CVs) of 12.8% and 7.7% for negative and positive controls, respectively. Furthermore, we observed higher clinical sensitivity and lower FNR with the BNZ2 assay in both the ED and compliance monitoring populations due to improved cross-reactivity for lorazepam and clonazepam metabolites. Despite these improvements, the BNZ2 assay was unable to detect 27% of specimens positive by LC-MS/MS, including specimens from patients using benzodiazepines without prescription.

Discussion

Due to its improved performance and rapid turnaround time, the BNZ2 assay should be implemented for UDS in the ED. However, the assay should not replace LC-MS/MS testing for compliance monitoring, as unsuspected benzodiazepine use may go undetected.

Bridging the gap: The critical role of laboratory developed tests in clinical toxicology

•Toxicology testing provides valuable information for patient management.•Current in vitro diagnostics (IVDs) are unable to meet all clinical needs.•Lab-developed tests (LDTs) in toxicology can be used to close clinical care gaps.•LDTs in clinical toxicology are almost exclusively mass spectrometry-based methods.

The analytical performance of six urine drug screens on cobas 6000 and ARCHITECT i2000 compared to LC-MS/MS gold standard

BACKGROUND

Immunoassays provide a rapid tool for the screening of drugs-of-abuse (DOA). However, results are presumptive and confirmatory testing is warranted. To reduce associated cost and delay, laboratories should employ assays with high positive and negative predictive values (PPVs and NPVs). Here, we compared the results of urine drug screens on cobas 6000 (cobas) and ARCHITECTi2000 (ARCHITECT) platforms for six drugs against LC-MS/MS to assess the analytical performance of these assays.

METHODS

Eighty nine residual urine specimens, which tested positive for amphetamine, THC-COOH, benzoylecgonine, EDDP, opiates and/or oxycodone during routine drug testing, were stored frozen until later confirmation by LC-MS/MS. Immunoassays were performed on cobas and ARCHITECT using a split sample. A third aliquot from these samples was tested by LC-MS/MS to assess the percentage of false positive, false negative, true positive and true negative results and calculate the PPVs and NPVs for each immunoassay.

RESULTS

The PPVs of THC-COOH and EDDP assays were 100% on both platforms. Suboptimal PPVs were achieved for oxycodone (cobas, 57.1% vs ARCHITECT, 66.7%), amphetamine (77.8 vs. 100%), opiates (80.0 vs. 84.6%) and benzoylecgonine (88.9 vs. 84.2%) assays. The NPV was 100% for cobas and ARCHITECT oxycodone assays. Lower NPVs were achieved for THC-COOH (cobas, 28.6% vs ARCHITECT, 25.0%), EDDP (72.7% for both assays), benzoylecgonine (74.4% vs 73.8%), amphetamine (83.3% vs 82.8%) and opiates (100% vs 85.3%).

CONCLUSION

Overall, cobas and ARCHITECT urine drug screens have comparable analytical performance. Confirmatory testing is warranted for positive test results especially for oxycodone, amphetamine, opiates and cocaine. Negative drug screen results must be interpreted with caution especially for THC-COOH, EDDP, benzoylecgonine, amphetamine and opiates.

Quantitation of Benzodiazepines and Metabolites in Urine by Liquid Chromatography–Tandem Mass Spectrometry

Background

Benzodiazepines (BZDs) are central nervous system depressants that are prescribed to prevent seizures, manage anxiety, or help sleep. When misused, BZDs can lead to addiction and sometimes cause death. Measurement of BZDs in urine is used to identify their use, especially in pain management settings. LC-MS/MS is preferred for these measurements because of its high sensitivity and specificity. Here, we report an LC-MS/MS assay for measuring 7 BZDs and metabolites in urine.

Methods

Urine sample was incubated at 60 °C for 30 min after addition of internal standards and a β-glucuronidase solution. After centrifugation, the supernatant was diluted with methanol and water before being injected onto a C18 analytical column in an LC-MS/MS system for quantification. The analytical time between injections was 4.35 min. The analytes included 7-aminoclonazepam, α-hydroxyalprazolam, α-hydroxytriazolam, oxazepam, lorazepam, nordiazepam, and temazepam.

Results

The lower limit of quantification ranged from 30 ng/mL to 50 ng/mL with an analytical recovery >80% for all 7 analytes. Total CV was <10% for all analytes (3 concentration levels of 100, 2500, and 5000 ng/mL; n = 30 each). This method had 100% agreement with a GC-MS method offered by an independent laboratory for negative urine samples. For the positive urine samples, this method showed a strong correlation (R > 0.96) with the GC-MS method.

Conclusions

The LC-MS/MS assay allows accurate and precise measurement of 7 BZDs and metabolites in a single analytical run with a short analytical run time and broad measuring ranges.

Risks, management, and monitoring of combination opioid, benzodiazepines, and/or alcohol use

The concurrent use of opioids, benzodiazepines (BZDs), and/or alcohol poses a formidable challenge for clinicians who manage chronic pain. While the escalating use of opioid analgesics for the treatment of chronic pain and the concomitant rise in opioid-related abuse and misuse are widely recognized trends, the contribution of combination use of BZDs, alcohol, and/or other sedative agents to opioid-related morbidity and mortality is underappreciated, even when these agents are used appropriately. Patients with chronic pain who use opioid analgesics along with BZDs and/or alcohol are at higher risk for fatal/nonfatal overdose and have more aberrant behaviors. Few practice guidelines for BZD treatment are readily available, especially when they are combined clinically with opioid analgesics and other central nervous system-depressant agents. However, coadministration of these agents produces a defined increase in rates of adverse events, overdose, and death, warranting close monitoring and consideration when treating patients with pain. To improve patient outcomes, ongoing screening for aberrant behavior, monitoring of treatment compliance, documentation of medical necessity, and the adjustment of treatment to clinical changes are essential. In this article, we review the prevalence and pharmacologic consequences of BZDs and/or alcohol use among patients with pain on chronic opioid therapy, as well as the importance of urine drug testing, an indispensable tool for therapeutic drug monitoring, which helps to ensure the continued safety of patients. Regardless of risk or known aberrant drug-related behaviors, patients on chronic opioid therapy should periodically undergo urine drug testing to confirm adherence to the treatment plan.

Optimizing urine drug testing for monitoring medication compliance in pain management

BACKGROUND

It can be challenging to successfully monitor medication compliance in pain management. Clinicians and laboratorians need to collaborate to optimize patient care and maximize operational efficiency. The test menu, assay cutoffs, and testing algorithms utilized in the urine drug testing panels should be periodically reviewed and tailored to the patient population to effectively assess compliance and avoid unnecessary testing and cost to the patient.

OBJECTIVE

Pain management and pathology collaborated on an important quality improvement initiative to optimize urine drug testing for monitoring medication compliance in pain management.

METHODS

We retrospectively reviewed 18 months of data from our pain management center. We gathered data on test volumes, positivity rates, and the frequency of false positive results. We also reviewed the clinical utility of our testing algorithms, assay cutoffs, and adulterant panel. In addition, the cost of each component was calculated.

RESULTS

The positivity rate for ethanol and 3,4-methylenedioxymethamphetamine were <1% so we eliminated this testing from our panel. We also lowered the screening cutoff for cocaine to meet the clinical needs of the pain management center. In addition, we changed our testing algorithm for 6-acetylmorphine, benzodiazepines, and methadone. For example, due the high rate of false negative results using our immunoassay-based benzodiazepine screen, we removed the screening portion of the algorithm and now perform benzodiazepine confirmation up front in all specimens by liquid chromatography-tandem mass spectrometry.

CONCLUSION

Conducting an interdisciplinary quality improvement project allowed us to optimize our testing panel for monitoring medication compliance in pain management and reduce cost.

Simultaneous quantification of urine flunitrazepam, nimetazepam and nitrazepam by using liquid chromatography tandem mass spectrometry

BACKGROUND

Benzodiazepines are used in hypnotics, sedation, and anti-anxiety. Recently liquid chromatography tandem mass spectrometry (LC-MS/MS) has been vastly developed for drug analysis in biological samples.

METHODS

We developed and validated a LC-MS/MS method for simultaneous quantification of flunitrazepam (FM2), nimetazepam and nitrazepam levels in 87 benzodiazepine positive human urine specimens by enzyme immunoassay. Deuterated analogues were used as internal standard.

RESULTS

The limits of quantification were found to be 0.25, 2.5, 5, 5 and 1ng/ml for FM2, 7-aminoFM2, nimetazepam, 7-amino-nimetazepam and nitrazepam, respectively. The intraday and inter-day CVs ranged from 0.6 to 4.6% and 1.2-9.4%, respectively. The within-day accuracy ranged from 80.8 to 108.7% and the between-day accuracy ranged from 80.5 to 118.0%. The recovery rate ranged from 70.5 to 96.7% for five different analytes. A group of 34 urine samples previously gas chromatography-mass spectrometry determined to contain 7-aminoFM2 was analyzed by this new LC-MS/MS approach. Quantitative data produced by both methods agreed well.

CONCLUSIONS

The LC-MS/MS method has proved to be robust and specific for the quantification of FM2, nimetazepam and nitrazepam in urine samples. This study also confirmed that nitrazepam and 7-aminonimetazepam are the metabolic products of nimetazepam.

Screening for drugs of abuse: which matrix, oral fluid or urine?

Urine is recognized as the prime matrix for drug test screening with well-established methods and testing protocols. Its major limitation is with regard to the inconvenience of sample collection and lack of integrity due to adulteration, dilution, drug spiking or sample exchange. The question is whether oral fluid, with its apparent better sample integrity, can replace urine for drug screening. This review examines the sample integrity problems and the advantages and limitations of oral fluid and urine in drug screening programmes. The variety of sample collection devices for oral fluid is shown to be a problem with recovery and detection for some drugs. This is examined in relation to the pharmacokinetics of drug metabolism and excretion in this matrix. Buccal contamination with drugs in oral fluid may also cause problems with interpretation. The clinical advantages of oral fluid analysis compared with urine testing are highlighted. Parent drugs are often found in oral fluid where only their metabolites may be found in urine, for example the benzodiazepines. 6-Monoacetylmorphine, an indicative marker of heroin, has a high prevalence in oral fluid from users of this drug but its detection in urine is limited due to its short half-life. Advances in analytical techniques, particularly chromatography linked to tandem mass spectrometry, are helping to promote oral fluid analysis. However, the lack of concordance studies examining both urine and oral fluid drug levels and kinetics in the clinical setting is of some concern.

Fragmentation of toxicologically relevant drugs in positive-ion liquid chromatography-tandem mass spectrometry

The identification of drugs and related compounds by LC-MS-MS is an important analytical challenge in several application areas, including clinical and forensic toxicology, doping control analysis, and environmental analysis. Although target-compound based analytical strategies are most frequently applied, at some point the information content of the MS-MS spectra becomes relevant. In this article, the positive-ion MS-MS spectra of a wide variety of drugs and related substances are discussed. Starting point was an MS-MS mass spectral library of toxicologically relevant compounds, available on the internet. The positive-ion MS-MS spectra of ∼570 compounds were interpreted by chemical and therapeutic class, thus involving a wide variety of drug compound classes, such benzodiazepines, beta-blockers, angiotensin-converting enzyme inhibitors, phenothiazines, dihydropyridine calcium channel blockers, diuretics, local anesthetics, vasodilators, as well as various subclasses of anti-diabetic, antidepressant, analgesic, and antihistaminic drugs. In addition, the scientific literature was searched for available MS-MS data of these compound classes and the interpretation thereof. The results of this elaborate study are presented in this article. For each individual compound class, the emphasis is on class-specific fragmentation, as discussing fragmentation of all individual compounds would take far too much space. The recognition of class-specific fragmentation may be quite informative in determining the compound class of a specific unknown, which may further help in the identification. In addition, knowledge on (class-specific) fragmentation may further help in the optimization of the selectivity in targeted analytical approaches of compounds of one particular class.

A fast liquid chromatography-tandem mass spectrometry method for determining benzodiazepines and analogues in urine. Validation and application to real cases of forensic interest

A fast liquid chromatographic/tandem mass spectrometric method was developed for the simultaneous determination in human urine of seventeen benzodiazepines, four relevant metabolites together plus zolpidem and zopiclone. The sample preparation, optimized to take into account the matrix effect, was based on enzymatic hydrolysis and liquid-liquid extraction. The separation of the twenty-three analytes was achieved in less than eight minutes. The whole methodology was fully validated according to UNI EN ISO/IEC 17025:2005 rules and 2006 SOFT/AAFS guidelines. Selectivity, linearity range, identification (LOD) and quantitation (LOQ) limits, precision, accuracy and recovery were evaluated. For all the species the signal/concentration linearity was satisfactory in the 50-1000 ng/mL concentration range. The limits of detection ranged from 0.5 to 30 ng/mL and LOQs from 1.7 to 100.0 ng/mL. Precisions were in the ranges 5.0-11.8%, 1.5-11.0% and 1.1-4.4% for low (100 ng/mL), medium (300 ng/mL) and high (1000 ng/mL) concentration, respectively. The accuracy, expressed as bias% was within ± 25 % for all the analytes. The recovery values, evaluated at 300 ng/mL concentration, ranged from 56.2% to 98.8%. The present method for the determination of several benzodiazepines, zolpidem and zopiclone in human urine proved to be simple, fast, specific and sensitive. The quantification by LC-MS/MS was successfully applied to 329 forensic cases among driving re-licensing, car accidents and alleged sexual violence cases.