Improved Clinical Sensitivity of a Reflexive Algorithm to Minimize False-Negative Test Results by a Urine Benzodiazepine Immunoassay Screen

Reflexive Drug Testing Strategies for Efficient Utilization of Resources and Better Interpretation

Urine drug testing is critical in managing the opioid crisis by providing insights into patient compliance and potential abuse. This review emphasizes the adoption of strategic approaches to improve test ordering and enhance the accuracy of interpretations. Risk assessment, pathologist oversight, and the application of a reflex algorithm can streamline laboratory workflows and support accurate interpretations, especially when navigating limitations from different testing methodology. Informatics tools can further optimize data analysis and testing workflows by increasing efficiency and integrating relevant clinical information. Together, these approaches lead to more effective urine drug testing, and ultimately improved patient care.

Practical Considerations for Implementing Immunoassays for Urine Drug Testing in Clinical Laboratories

This article provides an overview of urine drug testing (UDT), focusing on the principles and applications of immunoassays. It discusses the advantages and limitations of immunoassays compared to mass spectrometry, as well as common interferences that can lead to false positives and false negatives. Careful attention to analytical factors and awareness of potential preanalytical interferences can improve the accuracy and reliability of UDT.

Clinical Drug Testing Supporting Patients with Substance Use Disorder: A Review

BACKGROUND

Drug testing ordered to evaluate patients with substance use disorder (SUD) is not standardized. This may make drug testing difficult to interpret by the medical staff who order it.

CONTENT

In this review, a general overview of common drug testing strategies and potential knowledge gaps is discussed. This content is followed by discussion of how clinical laboratorians can support patients with SUD, through test offering optimization, development of drug interpretation services, and education on drug interpretation best practices.

SUMMARY

Clinical laboratorians are essential partners in healthcare delivery, particularly when providing interpretation of drug testing results. This review is intended to provide laboratorians with drug testing best practices to elevate their contribution to the healthcare system in supporting patients with SUD.

A computationally supported designer benzodiazepine strategy for public toxicology laboratories

Public laboratories must balance innovative and existing methods to keep up with designer drug trends. This article presents a strategy for handling designer benzodiazepines (DBZDs) in casework from screening to interpretation. The cross-reactivity of 22 DBZDs and metabolites was tested against the Immunalysis™ benzodiazepine (BZD) direct enzyme-linked immunosorbent assay kit. The kit had high intra-analyte precision (coefficients of variation <15%). Inter-analyte performance varied, triggering confirmation testing at concentrations ranging from 35 to 460 μg/L. The Cuyahoga County Regional Forensic Science Laboratory implemented a 40-analyte BZD and Z-drug confirmation method in 2019. Ten additional analytes were later validated for qualitative reporting, and the limits of detection for 13 analytes were lowered by 60%. The method of standard addition was also optimized for as-needed quantitation. Equal and 1/x weighting factors correlated well with target concentrations (coefficients of determination (r2) > 0.98), but 1/x weighting provided the most consistently accurate concentrations. Six computational models were developed to predict γ-aminobutyric acid-A receptor binding affinity to assist in case interpretation (r2 > 0.70 for cross-validation and test set prediction). These models were used to predict the binding affinity of analytes in the confirmation method. Other public laboratories can use this same practical strategy to adapt to any designer drug class (e.g., BZDs, opioids, cannabinoids and stimulants).

A case series evaluation of comprehensive drug testing in the pediatric acute care setting

Introduction

Drug testing typically follows a one-size-fits-all approach that is inadequate in some clinical scenarios, such as child maltreatment, neglect, and unintentional drug exposure. Results from immunoassay-based testing, which are non-specific, insensitive, and far from comprehensive, can lead to unintended consequences for children and their families.

Objectives

The objective of this retrospective case series study is to evaluate the utility of real-time (0-1 day) comprehensive drug testing as an alternative to immunoassay-based testing in the pediatric acute care setting.

Methods

Comprehensive drug testing results obtained by mass spectrometry testing and associated medical data for all pediatric cases (0-12 years) at one institution from 2019 to 2022 were included in the analysis. The final case series (n = 7) included all cases from patients <3 years with comprehensive drug testing results that were inconsistent with medication history and/or toxicology results by immunoassay.

Results

Comprehensive drug testing by mass spectrometry was ordered for 174 urine and blood samples representing 97 patients (0-12 years) from 2019 to 2022. Of these, 76 cases were from patients <3 years old; results were consistent with medication history and confirmatory for immunoassay results (n = 34), consistent with medication history (n = 14), confirmatory for immunoassay results (n = 10), negative (n = 9), or medical history was incomplete (n = 2). The remaining 7 cases were included in the final case series.

Conclusions

The cases highlight the value of real-time comprehensive drug testing in acute pediatric cases. Testing results can rule out toxic exposure from the diagnostic differential when negative, and lead to appropriate medical and social interventions when positive.