More Workers Are Testing Positive for Marijuana—and Cheating on Drug Screens

The percentage of U.S. workers testing positive for marijuana continues to climb as more states legalize the drug for medical and recreational use. The number of workers cheating on these screens is also increasing.

Marijuana positivity in the general U.S. workforce (not including regulated, safety-sensitive positions) increased to 4.5% in 2023, up from 4.3% in 2022 and 3.1% in 2019, according to annual drug-testing results compiled by Quest Diagnostics, one of the country’s largest drug-testing laboratories, based in Secaucus, N.J.

Quest conducted approximately 8.4 million urine-based drug tests on behalf of employers in 2023, in addition to 1.3 million oral fluid tests and 73,000 hair tests.

The percentage of U.S. workers testing positive for any illicit drug was 4.6%, the same as the last three years and down precipitously from 13.6% in 1988, when workplace drug-testing programs were initiated.

Cheating Increases

Worryingly, Quest found a significant rise in tampering with workplace drug tests, which typically takes one of two forms:

• Replacing urine specimens with someone else’s urine or synthetic samples found online.
• Submitting invalid specimens, which suggests they’ve been mixed with an additive. 

“Workers are cheating on drug tests at the highest rate in more than 30 years,” said Suhash Harwani, senior director of science for workforce health solutions at Quest. “Some workers are going to great lengths to attempt to subvert the drug-testing process.”

Approximately 6,000 urine samples out of about 5.5 million collected from the general U.S. workforce last year were classified as substituted. That’s more than six times the rate from the previous year and is the highest rate ever recorded by Quest.

About 25,000 drug tests were classified as invalid, which could indicate that someone mixed a urine sample with an additive—which can be bought online—designed to hide drug use. Invalid tests were up 45 percent in 2023 compared with the prior year, marking the highest rate ever reported by Quest.

Changing Laws May Lead to More Widespread Use of Marijuana

While overall drug use as evidenced by workplace testing has remained flat, positive tests for marijuana continue to increase. After marijuana, workers most often test positive for amphetamines; opiates, which are on a downward trend over the last five years; and cocaine. 

“It’s not surprising at all, considering that society is becoming more accepting of marijuana use and more states are legalizing it for either recreational or medical purposes,” said Kathryn Russo, an attorney in the Long Island, N.Y., office of Jackson Lewis. “More and more people are using marijuana, so it’s not surprising to see more positive test results.”

Currently, two dozen states and Washington, D.C., allow recreational marijuana use, according to the National Conference of State Legislatures. Marijuana remains a federally designated Schedule I drug, but the Biden administration is seeking to change that status, first assigned in 1970, to reclassify marijuana as a less-dangerous Schedule III drug.

Positive drug screens were particularly high in 2023 among white-collar workers, according to Quest. Marijuana positivity was up last year in 13 out of 15 industries, led by finance and insurance, which increased more than 35 percent. Positive tests for public administration and real-estate jobs rose by nearly 24 percent and more than 22 percent, respectively. Positive marijuana screens were also higher in fields such as education and professional and technical services.

“It isn’t clear why we’re seeing an increase in overall and marijuana drug positivity in office workers, but it isn’t a stretch that a combination of unprecedented stress and isolation during the pandemic and work-from-home policies may be contributing to greater drug use in employees in traditionally white-collar fields,” said Sam Sphar, vice president and general manager for workforce health solutions at Quest.

The rate of positive marijuana tests in states where the drug is legal under state law continues to outpace states where the drug remains illegal. States that have legalized recreational marijuana have seen the largest increases in positive tests. Among the regulated, safety-sensitive workforce, marijuana positivity decreased nationally from 0.98% in 2022 to 0.95% in 2023.

As for the huge jump in the number of workers cheating on their drug screens, “I’m not surprised with this either,” Russo said. “I can only speculate that as more people use marijuana, more people are trying to cheat drug screens to get a job. My advice for employers is to use a certified, reputable drug-testing vendor with trained professionals who know how to spot cheating at the collection facility. That’s really all an employer can do.” 

Compliance Patchwork Grows

Employers have been pushed to rethink their drug-testing policies in order to navigate laws that vary from state to state, and many are moving away from screening for marijuana at all.

“I am constantly having conversations with employers who are asking me whether they should stop testing for it,” Russo said. “They are still drug testing, but there is a trend toward moving away from testing for marijuana, especially for pre-employment and random tests. Either employers are saying they will not test at all or they will only test if it’s suspected that someone is impaired at work.”

Russo said that when she drafts multistate policies for workplace drug-testing, she includes a separate guidance document for managers to know the different rules in the different states where they operate.

And rescheduling marijuana to Schedule III will not clear up the questions and challenges that employers face when enforcing their drug-testing policies. That’s because if the rule is finalized, marijuana would likely be available for medical use with a prescription, but still not legalized at the federal level, Russo said.

“It may take a long time for the FDA to regulate marijuana,” she added. “In the meantime, employees already are obtaining it under state laws at state-approved dispensaries.”

Marijuana would most likely be regulated like a prescription drug. Employers can test for prescription medication if they are not penalizing people for lawful medication use, Russo said. “If someone is using a prescription drug without a prescription, employers can take an adverse action. Additionally, making marijuana a Schedule III drug still leaves a conflict with state recreational marijuana laws that permit use of marijuana without a medical prescription,” she said.