Marijuana in the workplace: Insights from the Drug Testing Index

Marijuana is number 1, just not in a good way. Marijuana is responsible for the vast majority of positive drug test results by far.

According to the 2025 Quest Diagnostics Drug Testing Index™ (DTI)¹ (an analysis of more than 8 million drug tests results from 2024), marijuana positivity for the general workforce from urine tests was 4.5%, far outpacing amphetamines, which was second at 1.7%.  For federally mandated tests (typically drug tests regulated by the U.S. Department of Transportation), marijuana was again the drug most often detected, at 0.87%, with amphetamines second at 0.80%.²  

When you combine those two populations, general and mandated, marijuana positivity was 2.9%, with amphetamines second at 1.4%.³

Interestingly, marijuana positivity from oral fluid tests in 2024 was 10.4%, with amphetamines next at 1.2%. From hair tests, marijuana positivity was 9.8% compared to 2.8% for cocaine, which was second.⁴

Quest Diagnostics has analyzed annual workplace drug testing data since 1988 and publishes the findings as a public service. Highlights from the DTI each year are released in a variety of formats, including in a series of tables that make it possible to compare drug test results by drug categories, drug testing methods, reasons for tests, and testing years, as well as other categories. Through Quest’s workforce health solutions, Quest Diagnostics is a leading provider of laboratory testing and other services designed to optimize the health, safety, and well-being of employees. For more information, visit WorkforceHealthSolutions.com.

The value of drug testing 

The results of the 2025 DTI help employers understand the value of drug testing and why they should think twice before dropping marijuana from their drug-test panel—when employees and job applicants fail a drug test, it’s usually because they’ve been using marijuana. And this trend has been increasing. 

Using the easy-to-read tables provided as part of the DTI, we can clearly see that marijuana positivity in the general workforce has been increasing annually, from 3.6% in 2020 to 4.5% in 2024. And in the federally mandated category, marijuana positivity increased from 0.79% in 2020 to 0.98% in 2023 before leveling off to 0.87% in 2024.⁵

Positivity in marijuana-friendly states

Perhaps to no one’s surprise, marijuana positivity is higher in states that have legalized the drug for either recreational use or for medicinal purposes. According to Quest’s 2023 DTI: 

“Marijuana positivity increased 11.8% (5.1% in 2021 versus 5.7% in 2022) in states in which recreational marijuana is legal and 8.3% (3.6% in 2021 versus 3.9% in 2022) in states in which medical marijuana is legal. In states in which neither recreational nor medical marijuana is legal, marijuana positivity increased 3.3% (3.0% in 2021 versus 3.1% in 2022) year over year and 14.8% over five years (2.7% in 2018 versus 3.1% in 2022).⁶” 

So, marijuana positivity rates are increasing just about everywhere, but faster and at higher levels in states that have legalized the use of marijuana.

Post-accident marijuana positivity levels

In Current Consulting Group’s (CCG) 2025 annual survey of employers co-sponsored by Quest Diagnostics, 78% of respondents indicated that promoting workplace safety is their top reason for conducting drug testing, 34 points higher than the second most common reason, to help hire the best possible job candidates. 

But 2025 DTI helps us clearly see how marijuana use by employees threatens their employers’ top drug testing objective of maintaining safe working conditions. According to the DTI: “Marijuana positivity following workplace accidents also remains high—post-accident positivity was 7.3% in 2024, just slightly below the record high of 7.5% in 2023.” 

The priority placed on safety as a reason for drug testing is significant because the implementation of recreational marijuana laws across the country is associated with a significant increase in workers’ compensation claims being filed.

According to the Workers' Compensation Research Institute’s (WCRI) 2025 report, enactment of a recreational marijuana law in a state leads to an increase in workers’ compensation claims, averaging a 7.7% increase in claim frequency at the 1.7-year mark and 15% by the fifth year. Workers in safety-sensitive jobs like transportation, construction, and mining and physically demanding jobs saw increases of 11.7% and 9.9% respectively.⁷

Now consider those findings in light of the fact that the average cost of a workers’ compensation claim is more than $44,000 or more than $90,000 when the accident involves a motor vehicle crash.⁸   

Conclusion

Thanks to the Quest Diagnostics Drug Testing Index™, we know that

1. Marijuana continues to show up in workplace drug tests more frequently than any other drug.
2. Marijuana positivity is increasing, especially in states that have legalized its use.
3. Marijuana positivity following workplace accidents remains at nearly the all-time high reported in the 2023 DTI.

Marijuana’s status as the number 1 illicit drug of abuse reported by the Quest DTI makes it easy to see the value of drug testing and that for most employers, especially those in safety-sensitive industries, it just makes good business sense to continue testing for marijuana.