SECAUCUS, NJ -- The percentage of employees in the general U.S. 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. This finding is part of a new analysis of nearly 9.8 million workforce drug tests released by Quest Diagnostics, provider of diagnostic information services.

The increase in substituted urine specimens in the general U.S. workforce, a population of over 5.5 million, was 633 percent (0.015 percent in 2022 versus 0.11 percent in 2023). Invalid urine specimens in the general U.S. workforce increased 45.2 percent (0.31 percent in 2022 versus 0.45 percent in 2023). A result of substituted or invalid suggests a specimen has been tampered with in an attempt to conceal drug use.i

The increasing rates of substituted or invalid specimens coincide with historically high rates of both general U.S. workforce drug positivity and post-accident marijuana positivity. Drug positivity in the general U.S. workforce was 5.7 percent in both 2022 and 2023. In 2023, in the combined U.S. workforce, urine drug positivity for all drugs was 4.6 percent, the same as in 2021 and 2022. This overall positivity is the highest level in more than two decades, up more than 30 percent from an all-time low of 3.5 percent in 2010-2012, and coincides with a sharp increase of 114.3 percent in post-accident positivity between 2015 and 2023 in the general U.S. workforce.

"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," said Suhash Harwani, Ph.D., Senior Director of Science for Workforce Health Solutions at Quest Diagnostics. "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."

Similar trends were also seen in the federally mandated, safety-sensitive U.S. workforce, with substituted specimens increasing 370.6 percent (0.017 percent in 2022 versus 0.08 percent in 2023) and invalid rates increasing 36.7 percent (0.30 percent in 2022 versus 0.41 percent in 2023).

"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."

Marijuana Drug Test Positivity Decreases in Federally Mandated, Safety Sensitive Workforce
In the federally mandated safety-sensitive workforce, marijuana positivity decreased nationally 3.1 percent year over year (0.98 percent in 2022 versus 0.95 percent in 2023).

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

"The federally mandated, safety-sensitive population has a lower rate of drug positivity, likely due to the fact that there is decreased drug use when there is an expectation of being drug tested. This is fundamentally the strength of having a drug testing program. The mere expectation of drug testing may be a deterrent, dissuading individuals from both drug use and applying for positions where such tests are standard practice," said Dr. Harwani

Post-accident Marijuana Positivity Continues to Climb
In 2023, post-accident marijuana positivity of urine drug tests in the general U.S. workforce was 7.5 percent. The new peak follows a steady increase in post-accident marijuana positivity every year from 2015 to 2023. In that 9-year time frame, post-accident marijuana positivity increased 114.3 percent.

The Quest data aligns with other reports associating marijuana legalization with workplace harms. A February 2024 study in the Journal of the American Medical Association (JAMA Health Forum) found recreational marijuana laws that allow recreational marijuana sales were associated with a 10 percent increase in workplace injuries among individuals aged 20 to 34 years.

"As the prevalence of marijuana positives in the workforce rises, our concern grows," said Mueller. "The data show an increasing correlation between marijuana use and adverse workplace effects, prompting a call for heightened vigilance and comprehensive strategies to safeguard workplace safety and productivity."

"Most employers are highly focused on productivity, which can be achieved by improving workforce health and wellness. A well-executed drug testing program can help an organization to maintain a healthier a workforce which, based on our data, could decrease the potential for accidents or other unsafe behaviors," added Dr. Harwani.

The Quest Diagnostics Drug Testing Index™ (DTI) is a series of reports that provide insights into trends in workforce drug use based on positivity rates of deidentified laboratory tests performed by Quest Diagnostics for a range of illicit, legal and prescription drugs. It examines test results according to three categories of workers: the federally mandated, safety-sensitive workforce; the general U.S. workforce; and the combined U.S. workforce. Federally mandated, safety-sensitive workers include pilots, bus and truck drivers, and workers in nuclear power plants, for whom routine drug testing is mandated by government agencies like the Department of Transportation, the Nuclear Regulatory Commission and the Department of Defense.

The strengths of the DTI analysis include its large, nationally representative sample size, longitudinal monitoring, a testing population that is generally reflective of the U.S. workforce and the quality of the company's drug testing services to confirm positive results. Limitations include analysis only of employers that perform drug testing with the company, and a lack of exact cross-specimen comparisons due to variations in substances for which employers test. Quest Diagnostics has analyzed annual workplace drug testing data since 1988 and publishes the findings as a public service.     

For more information, visit www.QuestDiagnostics.com/DTI.