FAILED stamped on a Drug Test Results form. Artwork created by the photographer.
(Credit: KLH49 / Getty Images)

More workers are tampering with employer-mandated drug tests than ever before, according to a new report from Quest Diagnosis, published Wednesday.

The annual Quest Diagnostics Drug Testing Index provides insights into patterns of drug use among the American workforce. It has examined positivity rates for workplace drugs tested by the company on behalf of employers since 1988. The current report offers analysis of almost 9.8 million workforce drug tests performed by the company last year.

“The percentage of employees in the general US workforce whose drug test showed signs of tampering increased by more than six-fold in 2023 versus the prior year, the highest rate ever in more than 30 years of annual reporting,” according to the report.

Invalid urine specimens increased by 45.2% year over year (0.31% in 2022 versus 0.45% in 2023). Substituted or invalid urine typical signal that the specimen has been tampered with to hide drug use, the company said.

“The increased rate of both substituted and invalid specimens indicates that some American workers are going to great lengths to attempt to subvert the drug testing process,” Suhash Harwani, PhD, senior director of science for workforce health solutions at Quest Diagnostics, said in a press release.

“Given the growing acceptance and use of some drugs, particularly marijuana, it may be unsurprising that some people feel it necessary to try and cheat a drug test. It is possible that our society’s normalization of drug use is fostering environments in which some employees feel it is acceptable to use such drugs without truly understanding the impact they have on workplace safety,” Harwani added.

Quest Diagnostics found that marijuana positivity in the general US workforce increased by 4.7% year over year (4.3% in 2022 versus 4.5% in 2023). From 2019 to 2023, marijuana positivity increased 45.2% (3.1% in 2019 versus 4.5% in 2023).

“Marijuana positivity stayed the same (1.1% in both 2022 and 2023) in states in which recreational marijuana is legal and decreased 2.2% (0.90% in 2022 versus 0.88% in 2023) in states in which medical marijuana is legal,” the data showed. “In states in which neither recreational nor medical marijuana use is legal, marijuana positivity decreased 6.7% (0.89% in 2022 versus 0.83% in 2023) year over year and stayed the same over five years (0.83% in 2019 versus 0.83% in 2023).”

As of February, recreational marijuana is legal in 24 states, plus Washington, DC. Another 14 states allow marijuana use for medical purposes only.

The results of Quest Diagnostic’s study jibe with those of a study published in February in JAMA Health Forum that showed that workplace injuries in states where recreational marijuana use is legal, there was with a 10% increase in workplace injuries among individuals aged 20 to 34 years. 

“Organizations must have sound policy and procedures to ensure employee drug testing programs have efficacy. Cheating on drug tests not only undermines workplace safety but also jeopardizes the safety of society as a whole,” said Katie Mueller, a senior program manager at the National Safety Council focusing on cannabis safety. “Companies, regulators and policymakers must prioritize accountability for the well-being of all individuals in our communities; lives depend on it.”