Microfluidic Platform for On-site Simultaneous Analysis of Ketamine and MDMA in Urine

Abstract

The abuse of psychoactive drugs such as ketamine and 3,4-methylenedioxymethamphetamine (MDMA) is increasing worldwide, and polysubstance abuse involving their concurrent use has become increasingly prevalent. Reliable on-site testing for both substances is therefore essential. However, conventional immunoassay platforms, including widely used commercial kits, remain limited in sensitivity and specificity for ketamine and MDMA compared with other drug metabolites, often leading to false negatives or cross-reactivity issues. To address these shortcomings, we introduce a microfluidic immunoassay-based on-site test device and validate its performance using certified reference materials and authentic urine samples. Authentic urine samples (N = 143), including drug-free controls (N = 45), ketamine-positive cases (N = 68), and MDMA-positive cases (N = 30), were evaluated. Verification results showed strong correlations (R2 = 0.87 and R2 = 0.90) between gas chromatography-mass spectrometry (GC-MS) data and the outputs of the developed device. Simultaneous detection revealed co-occurrence of ketamine and MDMA in 19.1% of ketamine-positive cases and 51.6% of MDMA-positive cases. These results demonstrate the practicality and necessity of simultaneous analyses, highlighting the accuracy, portability, and rapidity of the proposed device for on-site forensic drug monitoring.