Evaluation of the diagnostic performance of an oral fluid screening test device for substance abuse at traffic controls.

Introduction: The aim of this study was to evaluate the analytical performance of the Kite Biotechnology Oral fluid (OF) screening test device, which is used for roadside screening of cannabis, opiates, amphetamines, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), cocaine and benzodiazepines by comparing samples with matched plasma samples, analysed via liquid chromatography-tandem mass spectrometry (LC-MS/MS) for confirmation.

Methods: OF and plasma samples were obtained simultaneously from a total of 100 subjects. OF samples were analysed by OF screening test based on immunochromatography. The OF screening test cut-off values were 50 ng/mL for amphetamines (d-amphetamine) and methamphetamine/MDMA (d-methamphetamine), 30 ng/mL for cocaine (benzoylecgonine), 40 ng/mL for opiates (morphine), 20 ng/mL for benzodiazepines (nordazepam), and 25 ng/mL for cannabis (Δ-tetrahydrocannabinol). LC-MS/MS method validation was performed according to the CLSI C62-A recommendations with the following parameters: matrix effect, lower limit of quantification (LLOQ), linearity, intra-day and inter-day precision and accuracy.

Results: The overall specificity, accuracy and negative predictive values (NPV) were acceptable and met the DRUID standard of >80%. The OF screening test device showed good sensitivity for cocaine, amphetamines and opiates, whereas it indicated poor sensitivity for methamphetamine/MDMA (66.7%) and failed to detect cannabis and benzodiazepines.

Conclusion: The present study is the first report to evaluate the Kite Biotechnology OF screening test device. The diagnostic performance of the OF screening test device was acceptable for opiates, cocaine and amphetamines, but it was insufficient for methamphetamine/MDMA, benzodiazepines and cannabis because of sensitivity issues.