A rapid assay provides on-site quantification of tetrahydrocannabinol in oral fluid.
Tetrahydrocannabinol (THC), the primary psychoactive ingredient of cannabis, impairs cognitive and motor function in a concentration-dependent fashion. Drug testing is commonly performed for employment and law enforcement purposes however, available tests produce low-sensitive binary results (lateral flow assays) or have long turnaround (gas chromatography–mass spectrometry). To enable on-site THC quantification in minutes, we developed a rapid assay for oral THC analysis called EPOCH (express probe for on-site cannabis inhalation). EPOCH features distinctive sensor design such as a radial membrane and transmission optics, all contained in a compact cartridge. This integrated approach permitted assay completion within 5 min with a detection limit of 0.17 ngml THC, which is below the regulatory guideline (1 ngml). As a proof of concept for field testing, we applied EPOCH to assess oral fluid samples from cannabis users (