Can CBD Lead to a Positive Drug Test?
A June 2018-February 2020 study, led by researchers from Harvard Medical School and published online in the November 4, 2020 journal “JAMA Psychiatry”, found that those who consistently use full-spectrum, hemp-derived products may produce a positive result on a urine drug test. “It is often assumed individuals using hemp-derived products will test negative for THC. Current results indicate this may not be true,” the researchers wrote.
The 14 patients in the study took a milliliter of CBD three times per day for four weeks. The CBD in the study contained .02% of Delta 9-THC by weight. In the US, to be a legal hemp-derived product, the product must contain .30% or less of Delta 9-TH by weight. So the amount of Delta 9-THC in the current study product contained less than 1/10th the legal amount permissible for a hemp product. At the end of four (4) weeks, 50% of test subjects tested positive for THC-COOH on a urinary drug screen. The researchers noted that further study is needed to thoroughly assess the impact of variables that could lead to a positive test result.
The long list of those variables includes:
  • Amount of product use
  • Body mass index
  • Age
  • Sex
  • Race
  • Use of other medications
So what does this mean for Flight Attendants? Like the researchers said, individuals using hemp-derived products often assume they will test negative for THC. This study indicates that this may not be true and the user must be prepared for adverse consequence, including the loss of employment. 
Under DOT testing, there is no discretion afforded to the MRO to consider employee claims of CBD use. The MRO must report the result as a positive.