The drug testing method in question involves a common chemical analysis device called a gas-chromatography mass-spectrometry, or GC-MS, machine. Most such devices require the drug testing lab to add a chemical to a sample in order to identify trace amounts of illicit compounds, in a process called derivatization. Labs can perform derivatization using a variety of chemical agents, but one of the most common is called trifluoroacetic anhydride, or TFAA.
In June of 2018 , Mark Pennington received troubling news from his ex-girlfriend, with whom he shared custody of their 2-year-old son. She had taken a hair follicle from the boy, she said, and had it analyzed at a lab. A drug test had returned positive for THC, the intoxicating compound in marijuana; evidently their son had been exposed to it, presumably in Mr. Pennington’s presence. He was told that, from then on, he would be permitted to see the child only once a week, and under supervision.
Mr. Pennington was despondent about possibly losing custody of his child, until he spoke with Frank Conrad, the chief technology officer and lab director at Colorado Green Lab, a scientific consultant to the cannabis industry. Mr . Conrad directed him to a little-known study published in 2012 in the Journal of Analytical Toxicology that showed that a common forensic drug testing method could easily mistake the presence of CBD for THC. In short, the drug testing lab may have erred; it was entirely possible that the CBD Mr. Pennington had given his child had caused the drug test to produce a false positive for THC.
With Mr. Conrad as an expert witness, Mr. Pennington won equal custody. Now, on behalf of his son, he plans to sue the lab that did the drug test, to raise awareness of the problematic testing method, which could have broad implications for average Americans as CBD becomes mainstream.
CBD products sold outside of state-licensed marijuana dispensaries are not yet regulated. As a result, many products that claim to contain CBD in fact do not, or they may contain more than the legal limit of THC, according to testing done by the Food and Drug Administration . This could cause some CBD users to test positive for THC, and adds to the confusion surrounding THC testing generally. Dr. Sample said that this was most likely the problem with the CBD product Elizabeth had been using, and likely why her Quest drug test showed that she had used THC. But Elizabeth insisted that the CBD product she purchased did not get her high and did not have any THC.
It is also difficult to estimate how many people in a year have suffered negative consequences, such as the loss of a job or parental rights, after testing positive for THC, because most drug testing data is private. Even data that is public can be difficult to parse. For instance, in many locales, official statistics around “drugged driving” do not distinguish between drivers who test positive for THC and those who test positive for other drugs, such as cocaine or methamphetamine.
By Amanda Chicago Lewis
Other states, such as likeCalifornia, Montana, Oregon, and Washington have laws to assure that companies located in those states do not have to provide “reasonable accommodations” for people who use medical marijuana, and leave it up to each employer to decide, Reidy says. In those states, though, it’s still worth asking your company’s HR department about it if you’ve failed a drug test for marijuana after taking CBD.
Best bet: Consider products that are claimed to be “CBD only” and have COAs showing that they contain zero THC. Also, you can try tracking your own THC levels with an at-home drug test, says Mitch Earleywine, Ph.D., a professor of psychology at the University at Albany, State University of New York, who has studied the medicinal use of CBD. If you test positive but need to be THC-free, consider taking a two- to three-week break from the product to clear THC from your system, he says.
And those elevated levels might also be high enough to cause you not to pass a drug test.
Small Amounts of THC Can Build Up
Best bet: To increase the likelihood that a product doesn’t have more THC than claimed, look for a manufacturer that can provide a Certificate of Analysis, or COA, for its product. That document shows the results of a company’s testing for THC, CBD, and various contaminants. Though that testing is voluntary (except in Indiana and Utah) and the results aren’t confirmed by independent experts, for now it’s the best information available. If a store or website can’t provide you with a COA, look for another product. Read more about how CBD products are tested.
“I thought I was in the clear,” J.C. says. “From everything that I had heard, CBD oil wasn’t supposed to show up on drug tests.”
That’s what Horn, the truck driver from New York, alleges happened to him after taking a product advertised to contain “zero THC.”
But Sample says that CBD products could have more THC than the label claims. CBD products from hemp sold in retail stores and online aren’t supposed contain more than 0.3 percent THC, or tetrahydrocannabinol, the compound in marijuana that can get you high.