Earlier this month, the Office of the Secretary of Transportation issued a final rule allowing motor carriers to adopt oral fluid testing for all DOT-required testing types. During the proposal stage, some, including STC, had initially criticized the proposal pointing to shorter detection windows as a reason why it should not be allowed for pre-employment or random testing.

Advocates for allowing oral fluid testing for all DOT tests pointed to data from a reputable drug testing laboratory as evidence that oral fluids testing can be effective in identifying prohibited drug use. Specifically, the data showed that oral fluids testing positive rates for marijuana was 12.3% in 2020, compared to a meager 3.6% for urine. But how could that be? It has been widely reported that marijuana is detectable in a urine sample for up to 30 days. This is compared with oral fluids, whose reported detection window is a paltry 1-3 days.

It’s possible because the actual detection window for marijuana in urine may only be a fraction of the widely accepted 30 days. Dr. Todd Simo, Chief Medical Officer at HireRight and friend of STC pointed us to a literature review that points to research showing the detection window for marijuana using urinalysis at the current DOT cut-off rate of 50ng/mL for THC may be as short as two days for occasional users, and a mere ten days for heavy cannabis users. Dr. Simo suggested he thinks these studies may be more reliable than others because they included direct observation of users at in-patient cessation clinics versus previous research, which asked users to self-report when they last used marijuana following a positive test.

Of course, reasonable people will disagree about the studies upon which we should rely. What’s clear is that oral fluids testing holds great promise as an easily collected testing sample that may be just as effective as urinalysis and potentially even better. The testing technology and methods of detection are constantly improving, and we need to embrace these innovations to keep impaired drivers off the roads. Ultimately, these new techniques can offer more options and peace of mind as we manage employees that are in safety-sensitive positions