According to Robert Fitzgerald, a professor at the University of California, San Diego’s Center for Advanced Laboratory Medicine, “It would depend on the purity of the product.”
The simplest course is to refrain for a while, according to Kroner. But she also advised being up front about your CBD or CBN use — or any supplement use, for that matter — so that your test results can be interpreted in that light.
Licensed farmers can now grow the plant, as long as it contains less than 0.3% THC. The result? CBD is turning up in everything from oils and lotions to coffee and cookies.
It all points to the importance of taking “cross-reactivity” into account when a drug screening test comes back positive, Kroner said.
Why did only one test pick up CBN? The tests are known immunoassays — which means they use antibodies to detect drugs. Kroner explained that there are slight differences in the antibodies that test manufacturers use — so it’s possible to get different results.
Legally, Kroner noted, CBD products should only be produced from hemp plants with no more than 0.3% THC. But there’s no way for consumers to know for sure what’s in the products they buy.
A 2017 study found that about seven out of 10 CBD products did not contain the amount of cannabidiol stated on the label. And about one in five contained THC.
CBD products can still be problematic, however, when it comes to drug testing. Though drug tests screen for THC, not CBD, many CBD products contain a trace amount of THC which will be detected in your bloodstream during a drug test.
Topical products that claim to contain CBD—like shampoos, cosmetics or creams—should not cause any reaction during a drug test because they do not enter the bloodstream. In the case of CBD oils, gummies, teas or transdermal patches, the situation is more complicated. In a test of 84 CBD products obtained online, 18 contained THC.
Factors in CBD Oil Showing on Drug Screen
CBD has taken off as a natural remedy for a variety of ailments. CBD products like CBD oil can be made from either the hemp plant or the cannabis plant, which are closely related varieties of the same cannabis species, Cannabis sativa. CBD products contain a cannabinoid—a chemical—called cannabidiol, which does not make you high. The substance in marijuana that causes a buzz is a different cannabinoid, called THC, or tetrahydrocannabinol.
If you are concerned that THC in your CBD oil or other CBD product may show up on a drug test, you may be able to reduce the chance of that occurring, though there is no guarantee. Some of the factors that may increase the likelihood of a failed drug test are:
THC can be detected in a urine test for up to 15 days, depending on how often and how much you use. It leaves the bloodstream in about five hours, but substances your body makes from THC (THC metabolites) can show up for as long as 7 days. CBD tends to stay in the bloodstream from 2 to 5 days, depending on dosage and frequency. If you have been using CBD for a while, it can stay in your body for up to 30 days or more.