Roadside Cannabis Saliva Test for Impaired Drivers Closer to a Reality

Roadside Cannabis Saliva Test for Impaired Drivers Closer to a Reality

Most people are familiar with the consequences of drinking alcohol and then getting behind the wheel of a motor vehicle (car, truck, motorcycle, or boat). A driver can be stopped by the police and asked to take a breathalyzer test. If the test reveals that he has a blood alcohol content (BAC) over the legal limit for the state where the test is performed, the driver can be charged with DWI (driving while impaired) or DUI (driving under the influence).

At present, no test exists to test drivers for cannabis intoxication. Cannabis use is known to impair performance when driving, along with other types of activities. Researchers say they are a step closer to developing a saliva test that can be used at roadside stops. The need for such testing has become increasingly important due to several states allowing recreational marijuana use.

The scientists presented the results of their findings to the public through the American Chemical Society (ACS) SciMeetings online platform.

Driving After Using Marijuana Dangerous

Shalini Prasad, Ph.D., the head of the study, said that the general public thinks that driving after smoking marijuana is safer than driving after drinking alcohol. Both substances have similar effects on the body, however. They cause reduced awareness and diminished self-awareness. In the case of marijuana use, the blood level of THC (tetrahydrocannabinol), the active ingredient that leads to driver impairment has not been determined to a specific level as in the case of alcohol intoxication.

Prasad explained that this is still an emerging field and that early clinical reports are suggesting that between 1-15 nanograms of THC/ml of blood are high enough to be considered an impairment.

As marijuana is decriminalized in more states across the US, law enforcement agencies are faced with keeping roads safe from people who are driving after consuming the product. Blood tests to detect THC provide accurate results, despite being invasive and time-consuming. Not all police officers have the necessary training to collect a blood sample at a traffic stop.

Machine Developed to Detect THC in Breath Samples Using Cannabis Saliva Test

Some researchers are working on a machine that will measure THC levels in breath samples. It will work similarly to a breathalyzer that measures the alcohol level in a breath sample. Since THC in the saliva is similar to that in blood, Prasad and colleagues decided to develop a test that could provide quick, accurate results.

The researchers developed a device using THC sensor strips and an electronic reader. The sensor strips were coated with an antibody that binds THC so that it could be isolated from other substances present in saliva. The researchers added a drop of saliva containing THC to the strip and then inserted it into the electronic reader. The reader applied a set voltage to the strip and converted the data to a THC concentration.

They found their device was accurate for THC levels from 100 picograms/mL to 100 nanograms/mL. The test takes less than five minutes to administer and generate results. A field version of the test has been developed. In preliminary testing, saliva from a cheek swab is being used to screen for THC in settings similar to a traffic stop.