The US Federal DOT just came out with a reminder that being in a state approved medical marijuana program does not get you off the hook if your urine test is positive for THC.
So what is "positive for THC" and how would a CBD user test positive?
Urine tests for THC
This paper reviews the commonly used urine tests for THC measure two things:
- the screening test measures levels of 11-COOH-THC, with 50 ng/ml being the usual cutoff level for a "positive" test (caution: some labs use 20 ng/ml as the cutoff)
- the followup test measures TCHA and usual cutoffs for positive testing are around 15 ng/ml
I could not find any testing that specifically tests for CBD or its metabolites (please let me know if you are aware of any).
So a "positive urine THC test" means "urine levels of 11-COOH-THC over 50 ng/ml."
So how does a CBD user test positive for THC?
The problem with CBD users is that small residual amounts of THC wind up in the CBD they are using and are detected by these urine tests for THC. DOT and most employers will not distinguish between THC in CBD products and plain old THC. If they detect any THC in your urine, you are considered to have a "positive urine test for THC" with its consequences.
This article goes over the known laws impacting drivers as of April 2019 (Caution: we did not independently verify the findings of this article, so you should do your own verification before betting your career on its observations. )
- driving BETWEEN states (inter-state)_: CBD and THC are both forbidden by federal law
- driving WITHIN a state (intra-state): it depends on the state, but positive THC in the urine is still considered a violation.
So the only way that someone who uses only CBD could have a positive THC urine test would be if their CBD were contaminated by THC. Unfortunately, there is a lot of CBD out there with THC in it, and you can't tell just by reading the label. Many manufacturers don't bother to test their products so even they don't know.
There are, however, CBD isolates that contain 99.5 % CBD. CBDistillery has a whole line of products like this. You have to look at the individual product testing sheets, which responsible CBD manufacturers put on their websites. Look for "total THC" found by the testing lab. The last time I looked up testing on CBDistillery Isolate powder, the total THC was undetectable. So this product contains CBD but the testing lab cannot find any THC in it.
So this article is just information. We do not recommend any manufacturer or product, nor do we recommend anyone break any law. However, it appears that CBD consumers may be able to decrease inadvertent positive THC urine tests by a judicious choice of product. As always, YMMV, you assume all risks, we are just providing publicly available information.