National Cannabis Testing Day

Why 4/21 is Considered “National Drug Testing Day”

April 20 (4/20) is, of course, followed by April 21 (4/21), which has come to be understood as the unofficial “National Drug Testing Day” – especially for cannabis. And, because most employers use urine or oral fluid testing that have detection windows for cannabis ranging from many hours to several weeks after use, any employee who celebrates 420 and is tested by their employer on 4/21 is likely to fail. 

Most employers put drug testing policies in place to deter on-the-job use and detect it if it does happen. With an end goal to protect both employer and employees from physical and financial harm – not to monitor employees’ legal choices outside of work – detecting specifically isolated recent (as opposed to past) use enhances deterrence policies in a way that promotes compliance with an employer’s drug testing policy.


With cannabis now widely legal, many employers are struggling to figure out how to maintain the important detection and deterrence benefits of drug testing without penalizing employees who choose to use cannabis legally and responsibly during personal time. They still need to know whether someone uses cannabis at, or immediately before, work, but recognize that finding out a person smoked cannabis at a concert a couple of weekends ago is no more relevant than learning they’d had a beer at that same event.

Many employers have seen how the consequences of failing a drug test can be both devastating to an employee and costly to the employer – expenses that aren’t making the workplace any safer if the failed drug test was due to cannabis use days or weeks ago. Even outside of 420, use is increasing in industries that are either not safety-sensitive or are “safety-light.” But of the positive tests that indicate this increase, how many are due to past use and not use immediately before or during work?

Conventional cannabis tests can give information about IF a person smoked, but not WHEN, and there is no way to modify the cutoff levels of those tests or analyze the test data in depth to specifically isolate recent cannabis use. They need a new solution. 


Fortunately, new technologies are on the horizon to offer a better approach. THC (the psychoactive component in cannabis) only stays in the breath for a few hours after use. Testing breath (rather than urine, oral fluid, hair, or blood) for cannabis will allow employers to identify whether someone used cannabis very recently –  not whether they used the day, week, or month prior. To use a concrete example, when available, the HOUND® CANNABIS BREATHALYZER will not fail someone who used cannabis after work on 4/20 but sobered up before their shift on 4/21.

The HOUND® CANNABIS BREATHALYZER answers the most relevant question when it comes to maintaining safe, fair workplaces: Did this person use cannabis recently? That information allows employers to maintain safe workplaces while allowing employees to make private decisions about cannabis use during their personal time. This helps keep workplaces safe, turnover costs low, and employees happy.

That’s the case every day of the year – not just on 4/21.

To stay up to date on the science of breath testing and the future of drug testing, subscribe to our monthly newsletter or connect with our sales team to learn how Hound Labs can help you balance workplace safety with employee fairness and privacy.

April 21, 2022

Director of Marketing