A Comprehensive Evaluation and Error Rate Assessment of Field Colorimetric Testing for Seized Drugs

The proposed research aims to address critical gaps in the understanding and evaluation of color tests used in the field by law enforcement and in forensic laboratories. The study seeks to achieve several goals: (1) to comprehensively characterize the performance of field color tests; (2) to assess the inherent accuracy, reliability, and error rates of these tests and to explore the operational influences on test reliability; and (3) to evaluate the impact of real-world sample compositions on test performance.

This project is separated into three discrete phases. Phase 1 will characterize the performance of routinely used field-based color tests in a controlled environment to understand the potential extents and limitations inherent to the color test chemistry. This phase will use standard reference materials (including adulterants, excipients, and other commonly found substances) to generate color test results for establishing metrics that include sensitivity, specificity, and temporal impacts on these results. Phase 2 will characterize the performance of field-based color tests in a controlled environment to understand the potential extents and limitations that can be operationally induced because of procedural variabilities. This phase will focus on exploring the effect of operational influences on the reliability and accuracy of the color tests. Variables, including user interpretation of results, sample amount, reagent mixing, procedural steps, and storage conditions, will be investigated. Finally, Phase 3 will evaluate the potential impact of sample quality and composition on the performance of presumptive color tests. This phase will further characterize field color tests using adjudicated seized drug samples to assess the impact of real-world sample compositions and mixtures on test performance. Adjudicated samples will be analyzed using both field color tests and confirmatory analytical techniques, and the results will be compared to identify potential sources of error and determine error rates. This will allow for a comprehensive assessment of errors across distinct categories (e.g., specific test used, sample compositions, drug classes) to identify any trends that may be present. In all three phases, collaborative support from leading expert practitioners across the multidisciplinary criminal justice ecosystem will be leveraged to ensure the relevance, impact, and dissemination of the research findings.

Ultimately, this research aims to contribute to evidence-based policy considerations regarding the use of field color tests in the criminal justice system, potentially leading to improved practices in both field and laboratory settings. CA/NCF