Companies struggle to interpret marijuana test results

After recreational marijuana use became legal in some states, the Society of Human Resource Management conducted a multi-state survey that found many employers vowing to get tougher in response, strengthening their workplace drug policies and maintaining a zero-tolerance attitude toward the drug. “But they backed off because they had a lot of people testing positive,” says Tamara Cagney, CEAP, board member of the Employee Assistance Professionals Association (EAPA).

In states where recreational use is legal, there have been serious questions about whether it’s counterproductive to conduct pre-employment testing for marijuana. “Employees think it’s legal, so it’s no problem,” says Cagney, who heads the internal EAP at Sandia National Laboratories in Livermore, Calif. For those employers that continue to test, interpreting the results in the context of maintaining a safe workplace poses a major challenge as well.

Urine testing cannot detect impairment, particularly for marijuana, which stays in the body days—even weeks—after use, notes Cagney. “All of the pre-employment testing is presence testing, not impairment testing,” she says. The percentage of people who use marijuana recreationally and then develop a substance use disorder is similar to that for alcohol: about 10%, says Cagney. “But that doesn’t mean it’s a no-consequence drug,” she says. The problem is that there is no technology that will detect whether someone came to work impaired by marijuana.

With alcohol, breath tests reveal blood alcohol content, which already has been linked to impairment by drunk-driving statutes. With the science not there to determine whether someone is under the influence of marijuana, says Cagney, “This puts employers between a rock and a hard space—say someone uses marijuana and is operating a forklift, but you don’t know if he is impaired?”

All a positive urine test means is that a substance has been used, says Louis Baxter, MD, FASAM, president and executive medical director of the Professionals Assistance Program of New Jersey. For impairment, breath (for alcohol) or blood would need to be tested, as often occurs in a post-accident situation, Baxter says.

In addition to pre-employment testing, there is “for-suspicion” testing, when a supervisor can request a drug test if an employee seems to be acting impaired, something that the supervisor is particularly concerned about in safety-sensitive situations.

Susceptible industries

“But here’s the real problem,” says Baxter. “I’ve noticed over my 30 years of practice that many individuals who work in construction and landscaping actually choose those occupations because they have a substance use disorder,” as they are attracted to jobs where they can go to work and not be observed by supervisors. Ironically, however, these also are the professions that are most likely to resist pre-employment testing for marijuana, because of the high positive rate among candidates and the consequence of not having enough workers, according to an article published in The New York Times in May.

Marijuana use (based on the National Survey on Drug Use and Health) and marijuana positivity rates in the workforce (based on the Drug Testing Index) are both rising. In the general workforce, based on urine tests, marijuana positives went up 5% in 2013 and 14% in 2014. Oral fluid testing, which is more sensitive, has found even steeper increases, with positive rates going up 25% in 2013 and 17% in 2014.

Barry Sample, PhD, director of science and technology at Quest Diagnostics, a national laboratory that has been conducting workplace drug tests for decades, says that even in the states that have legalized recreational use, he has not seen any indication that employers don’t want to test for marijuana. “We’ve heard the concerns,” Sample says. “But it depends on the employer; there’s not a wholesale turning away.”

Meanwhile, employers across the country are watching what is happening in Colorado, says Cagney. “The first year of legalization in Colorado, positives went up 23%. That’s huge.”

But what employers really need to know about is whether those people are impaired, says Cagney. And right now, it’s impossible to tell that with a biometric test. “They could do coordination testing, impairment testing, put you on a video game to see if your concentration is good enough to operate machinery,” she says, in the way the San Diego trolley company did in the years before drug testing. “They don’t care if you’re on drugs or you have a new baby and can’t sleep. If you can’t operate the trolley, that’s what they want to know.”

Companies do have a moral obligation (and in some industries, a legal one) to refer employees to treatment, and not to terminate them, if they test positive on random or for-cause tests, indicates Baxter, author of a white paper on drug testing published by the American Society of Addiction Medicine (ASAM). He also thinks it would be a good idea for all employers who conduct pre-employment tests to tell the individuals who test positive that they need to pursue further assessment and treatment. But he adds that there is “no obligation” for employers to tell job candidates anything.