THC Metabolites Detected in Urine Following Full-Spectrum CBD Use

The November 4, 2020 issue of JAMA Psychiatry published results from a recent study examining whether the use of full-spectrum CBD from legal hemp (< 0.30% Δ9-THC) would lead to positive urine test results for THC metabolites.

It has been often assumed that hemp-derived cannabidiol products will test negative for urinary THC.  However, the study showed that half of subjects tested positive for carboxy-THC, an inactive metabolite of Δ9-THC, after four weeks of daily use.  Samples were initially screened through urine drug assays.  Positive screens were confirmed through gas chromatography-mass spectroscopy.

The results suggest that individuals consistently using full-spectrum, hemp-derived products may have positive urine tests.  The sample size was relatively small (14) so studies with larger sample sizes will be needed to address what other variables, i.e., product use, BMI, age, race, sex, medication use, etc., contribute to positive findings.  Interestingly, the study product contained only 0.02% Δ9-THC by dry weight.  Hemp-derived products in the US can legally contain 0.30% Δ9-THC, which is more than 10 times the amount of  Δ9-THC as the study product.

What does this mean for Iowa drivers? It is explicitly legal to possess hemp-derived CBD after the passage of SF 599 and HF 2581.  It is a crime, however, under Iowa Code Chapter 321J to drive with any detectable amount of a THC metabolite in your system, even if it is inactive like carboxy-THC.  Currently, there is no way to distinguish between Δ9-THC metabolites from hemp and marijuana in urine.

Perhaps it is time for the legislature to carve out a carboxy-THC exception in Chapter 321J so that consumers aren’t held criminally liable for driving with a lawful supplement on board?

GRL Law.  We know hemp.