It is standard in the U.S. for police to use blood or urine samples to test for marijuana. But those tests only indicate if marijuana is in an individual’s system, and not when marijuana was used or how much.
The former Chief of Chemistry and Drug Metabolism at the National Institute on Drug Abuse (NIDA), Marilyn Huestis, says saliva testing provides more accurate results, Oregon Live reports.
Huestis said, “I believe that we should be documenting impairment, and then we should be using oral fluid. It’s noninvasive, doesn’t require medical personnel to draw it, it doesn’t’ require a person to be stuck by a needle.”
Saliva can be tested immediately to detect up to eight different compounds, which could drastically change roadside DUI drug testing by the police. Saliva could reveal a person’s recent marijuana usage, while urine and blood can be inaccurate as inactive marijuana metabolites can remain in the body for weeks depending on the frequency and quantity of marijuana used.
The saliva method is already used in Europe and Australia. Huestis notes that the incidences of impaired driving have reduced since the implementation of saliva tests in those regions.
She speculates that the implementation of saliva testing for marijuana use would be more accurate in determining impairment and policies would be easier to create, in her opinion, if this method of testing were used.