Drivers who are intoxicated with alcohol, while driving, are often subjected to roadside stops, in the United States, where they are asked to take breathalyzer tests and would further have to go through stiff penalties if the alcohol content in their blood exceeds the legal limitations. However, there is no current test that exists, for cannabis intoxication.
Scientists have now reported that they are another step closer to the invention of a convenient saliva test that will measure the cannabis levels at roadside stops. American Chemical Society (ACS) SciMeeetings online platform, will be where the researchers will be presenting their results.
According to Shalini Prasad, Ph.D., who led the study, people usually tend to think that drunk driving is worse than driving after smoking cannabis and consider the latter to be relatively “safer”. However, she further explained how both substances can cause similar effects in the body such as slowed reaction time, diminished alertness, and reduced self-awareness.
Tetrahydrocannabinol (THC) is the psychoactive compound in cannabis and constitutes impairment. However, the safe levels of THC in blood, unlike alcohol, have not been well characterized. According to Prasad, despite it being an emerging field, 1 to 15 nanograms of THC per milliliter of blood, is suggested by the preliminary clinical reports, to be considered a level of impairment.
The law enforcement agencies are focusing on how to keep the roads safe from high drivers, as more U.S states continue the decriminalization of cannabis. The blood tests for THC are time-consuming and invasive, despite the accuracy. Along with that, this is not a convenient test for many police officers to perform skillfully at roadside stops. Some researchers are working on a cannabis test that would be similar to a breathalyzer for alcohol, to measure THC levels in the breath.
However, according to Prasad, extensive and error-prone data processing would be required to filter out the effects of other compounds as the levels of THC are low in the breath. Consequently, focusing on the close correlation between saliva and blood, Prasad and colleagues aimed at the development of a saliva test for THC that would be simple, quick and accurate.
THC sensor strips and an electronic reader were engineered by researchers at the University of Texas at Dallas. The sensor strips contained two electrodes and were coated with an antibody. The antibody binds with THC and isolates it from other compounds in the saliva. According to Prasad, the antibody is used, to focus only on the needle in the haystack.
The researchers performed the test by adding a tiny drop of human saliva that was spiked with THC, on the strip. The strip was then inserted into the electronic reader, which further applied a specific voltage. The electric current changed due to the occurrence of the polarization between the interacting antibody and the THC surfaces, shortly after the THC attached to the antibody. THC concentration would then be traceable after the conversion of data by the e-reader.
However, for THC levels ranging from 100 picograms per milliliter to 100 nanograms per milliliter, the device held accuracy. According to Prasad, this prototype was the first to be able to report both low and high concentrations of THC, with high sensitivity and specificity. Furthermore, the test requires less than five minutes to perform and complete.
Due to legal issues regarding cannabis in Texas, THC spiked saliva is what researchers are working with rather than actual cannabis smokers. However, law enforcement agencies and researchers from other states where cannabis is legalized, are interested in collaboration.
Additionally, lawmakers and regulatory groups have shown interest to develop effective laws by using the data generated by the device.