Finding out if someone is operating a vehicle while intoxicated with THC, the main substance found in marijuana, can only be done by taking urine or blood samples back to the lab, but that process could change dramatically with a new invention.

Developed in the laboratory of Shan Xiang Wang at Stanford University, California, the technology, which is merely a proof of concept for the time being, works similarly to a breathalyzer and can detect traces of marijuana in saliva in just three minutes, as DigitalTrends reports.

Detection of marijuana from blood or urine in a reference lab is not difficult, but it is difficult or impractical at the roadside. Most law enforcement officers are not authorized to take blood samples, while taking a urine sample on spot is extremely inconvenient. Detection of marijuana from saliva would bypass the trappings with either blood or urine samples”, professor Wang said.

If everything goes as planned, then law enforcements could use the devices, which connect to smartphones via Bluetooth, within a year or so, as Wang’s laboratory will now focus on turning the proof of concept into a fully-functional handheld gadget, one that could turn out to be as revolutionary as breathalyzers, used for estimating blood alcohol content, which date back to the 1930s.

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