The sharp increase in fentanyl in random drug checks suggests more workers are using the opioid after they have passed pre-employment screens.
Fentanyl positivity rates in random workplace drug testing exceeded pre-employment screening by more than 700%, according to the 2025 Quest Diagnostics Drug Testing Index.
The analysis of more than 8 million drug tests found fentanyl positivity rates of 1.13% in random testing compared to 0.14% in pre-employment screening among the general US workforce in 2024. This difference contrasts with other drug categories, where marijuana showed 42% lower positivity in random testing versus pre-employment screening over the past five years.
“The new Quest data indicates a worrying increase in fentanyl positivity in random drug tests as well as fentanyl drug-combining among the nation’s workforce in day-to-day work environments,” says Suhash Harwani, PhD, senior director of science for Workforce Health Solutions at Quest Diagnostics, in a release.
Co-Positivity Rates Rising
The data revealed that 60% of fentanyl-positive specimens in 2024 also tested positive for other drugs. Notably, co-positivity with marijuana doubled from 10% in 2020 to 22% in 2024. Amphetamine co-positivity also increased, rising from 11% in 2020 to 16% in 2024.
Despite the fentanyl data, overall workplace drug positivity declined slightly to 4.4% in 2024 from 4.6% in 2023. However, this rate remains elevated, with positivity rates of 4% or higher persisting over the past decade.
Marijuana continues as the most frequently detected substance, maintaining steady positivity at 4.5% in the general workforce. Post-accident marijuana positivity remained high at 7.3% in 2024, just below the record 7.5% recorded in 2023.
Amphetamines showed continued increases, rising to 1.7% from 1.5% in 2023. Several opioids demonstrated ongoing declines, with 6-AM (heroin metabolite) decreasing to 0.004% and opiates declining to 0.13% from 0.14% in 2023.
Testing Circumstance Variations
Drug test positivity varied significantly based on testing circumstances. For-cause testing in the general workforce showed 33.1% positivity in 2024, down from 39.4% in 2023. Post-accident testing declined slightly from 10.4% to 10.2%, while return-to-duty testing decreased from 8.4% to 7.9%.
Among federally mandated safety-sensitive workers, who face stricter testing protocols, positivity rates were consistently lower across all testing categories compared to the general workforce.
Regulatory Context
The Department of Health and Human Services’ Federal Drug-Free Workplace Program added fentanyl to the authorized drug testing panel effective July 7, 2025. This regulatory change reflects growing recognition of fentanyl’s workplace impact, as the CDC estimates that 7 out of 10 overdose deaths involve illegally manufactured fentanyls.
The Quest Diagnostics Drug Testing Index analyzes deidentified laboratory test results across three worker categories: federally mandated safety-sensitive workforce, general US workforce, and combined US workforce. Quest Diagnostics has published these annual workplace drug testing analyses as a public service since 1988.
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