Roadside saliva test could detect cannabis use

Even though driving while high can be just as dangerous as driving drunk, there's currently still little in the way of devices that can be used for roadside cannabis-use checks. That could be about to change, though, thanks to research being conducted at the University of Texas at Dallas.

Led by Prof. Shalini Prasad, scientists at the university are developing a system that incorporates disposable test strips, and a compact portable reader device.

Each strip incorporates two electrodes, and is coated with proteins that bind only with THC, which is the psychoactive compound in cannabis. Once a person's saliva sample has been applied to a strip, that strip is placed in the reader, which runs an electrical current through it.

Because the proteins exhibit different qualities when bound with THC, the current increases in accordance with how much of the compound is present in the sample. By measuring that increase, the reader is therefore able to calculate THC levels in the bloodstream, which closely correlate with those in the saliva.

The testing procedure can reportedly be performed onsite in under five minutes, and is capable of measuring THC levels ranging from 100 picograms per milliliter to 100 nanograms per milliliter of blood – according to Prasad, previous research suggests that a minimum of 1 to 15 nanograms/ml constitutes impairment.

"This is the first demonstration of a prototype device that can report both low and high concentrations of THC in a noninvasive, highly sensitive and specific manner," she says.

A report on the study was recently featured on the American Chemical Society's SciMeetings online presentation platform.

Source: American Chemical Society