Researchers at Johns Hopkins Medicine have published a paper in the Journal of Analytical Toxicology demonstrating that the vaping of some legal hemp products may yield a cannabis-positive result on a drug test.
By federal definition, hemp may contain no more than 0.3 percent delta-9 tetrahydrocannabinol (THC), the psychoactive substance in cannabis that causes the high.
In a study involving six participants, two tested positive after vaping cannabis that contained 0.39 percent THC, 10.5 percent CBD, and a 27 to 1 ratio of CBD to THC that is similar to common hemp and CBD products.
For the study, three women and three men with an average age of 31 each vaporized a little less than a gram of cannabis which they inhaled from balloons.
The total dose contained 100 milligrams of CBD and 3.7 milligrams of THC.
While the THC concentration in the cannabis used in the study did not meet the federal definition of hemp, it exceeded the maximum amount by only 0.09 percent.
“Because the market for CBD products is so new and the popularity of use is growing so quickly, we want the public to be aware that a positive drug test is possible,” says Associate Professor of Psychiatry and Behavioral Sciences at Johns Hopkins University School of Medicine Ryan Vandrey, Ph.D. “I have a hard time finding anyone who hasn’t used a CBD product at least once, but most are completely unaware of the possibility of THC exposure or a positive drug test as a result of using these newly legalized products.”
In addition to vaporizing high-CBD/low-THC cannabis, study participants were given a pure CBD capsule, vaporized pure CBD, and a placebo in three separate dosing sessions conducted one week apart.
For the urinalysis, a concentration of at least 50 nanograms per milliliter of THC-OOH (a metabolized form of THC) would produce a cannabis-positive result.
Positive results were then confirmed at a 15 nanogram per milliliter cut-off using a more sensitive test.
Two out of the six study participants who vaped the low-THC/high-CBD cannabis tested positive for THC.
Vandrey says that the results suggest that CBD by itself will not cause a positive drug test, though not much THC is required to produce a positive result with some people.
According to Vandrey, factors such as individual drug metabolism and inhalation depth may contribute to the breakdown or buildup of cannabinoids in the body.
The research team plans to repeat their studies using products that meet current federal hemp regulation standards for THC content and also study the impact of repeated CBD and hemp exposure on drug test outcomes.
