Performance of a point-of-care device for oral fluid ketamine evaluated by a liquid chromatography-tandem mass...

The performance of a point-of-care device, the OratectXP Oral Fluid Drug Screen Device for Ketamine, was evaluated. The cutoff specification for the device was for ketamine at 15 ng/mL. A total of 72 authentic oral fluid samples were collected from volunteers at two local rehabilitation centers for clients with addiction to drugs of abuse. These samples were tested with the device for visual detection of ketamine and also measured by a liquid chromatography isotope-dilution tandem mass spectrometry method for ketamine, norketamine and dehydronorketamine concentrations. Sensitivity of the device was 87.5% when tested by 24 authentic oral fluid samples with ketamine concentrations ≥ 15 ng/mL. False positive rate of the device was 4.5%. Specificity of the device was 97.9% when tested by 48 authentic oral fluid samples with ketamine concentrations < 15 ng/mL. False negative rate of the device was 6%. The overall efficiency of the device was 94%. According to the desirable acceptance criteria proposed by the "Driving Under the Influence of Drugs, Alcohol, and Medicines" project, the performance of the OratectXP was satisfactory and achieved the minimum standard for testing drivers under the influence of drugs. Furthermore, we propose the confirmation cutoff level for oral fluid ketamine to be at 25 ng/mL.