Media reported that even though drug driving is as dangerous as drink-driving, there are still few devices used for roadside marijuana use checks. But that could change, thanks to research by the University of Texas at Dallas. Led by Professor Shalini Prasad, scientists at the university are developing a system that combines a one-time test strip with a compact portable reader device.
Each strip contains two electrodes and is coated with a protein that binds only to tetrahydrocannabinol (THC), a psychoactive compound in cannabis. After applying a person’s saliva sample to the test paper, place the test paper in the reader, which will flow through the current. Because proteins exhibit different masses when combined with THC, the current increases depending on the number of compounds present in the sample. By measuring the increase, the reader is thus able to calculate the THC level in the blood, which is closely related to the THC level in saliva.
The test procedure is reported to be performed in the field within five minutes and can measure THC levels ranging from 100 grams per milliliter to 100 ng per millilitre – previous studies have shown that a minimum of 1 to 15 ng/ml poses damage. “This is the first demonstration of a prototype device that can report low and high concentrations of tetrahydrocannabinol in a noninvasive, highly sensitive and specific manner,” she said. “
The study was recently presented on the American Chemical Society’s SciMeetings online demo platform.