The value of hair testing

We hear a lot about urine drug testing, and rightfully so; after all, it’s the most common drug testing method used by employers. In recent years, we’ve also heard a lot about oral fluid testing, especially since the US Department of Transportation (DOT) issued a final ruling that when fully enacted will allow covered employers in the transportation industry to choose oral fluid tests in addition to or in place of urine tests. But did you know that another drug testing method produces the highest rate of positive test results?

The growing impact of hair testing in workforce drug screening

According to the 2026 Quest Diagnostics Drug Testing Index (DTI), “Hair test positivity among American workers reached 19.1% in 2025, potentially reflecting recurring or chronic drug use.”

Nearly 1 in 5 workers in the general workforce testing positive on hair tests represents nearly a 46% increase from the 13.1% reported by the DTI for 2021. This eye-catching increase is significant by itself, but when compared with urine positivity rates, which have remained steady for more than a decade at just above 4%, it’s astounding.

Thanks to Quest Diagnostics, which has been analyzing and sharing workplace drug testing data annually since 1989, employers have the ability to compare positivity rates by drug categories, drug testing methods, reasons for tests, testing years, industries, and a host of other categories. Click here to see detailed results beginning in 1989 presented in easy-to-read tables and charts.

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 wellbeing of employees. For more information about how Quest may help you improve the health and safety of all your employees, visit Quest Workforce Health Solutions.

What the 2026 DTI reveals about workforce drug use trends

According to this year’s DTI, drug use by employees is not decreasing. Quoting from the DTI report: “Drug use positivity for the combined workforce held at 4.3% in 2025 in urine drug tests, compared to the rate of 4.4% in 2024. The rate was 4.6% from 2021 to 2023. The last year the rate was as low as 4.2% was 2017.

And as most employers would probably predict and the DTI makes clear, marijuana use is at the heart of the problem. Marijuana continues to be the primary driver of positive drug tests across all specimen types, including urine, hair and oral fluid, and among all workforce segments.

Marijuana positivity across specimen types: Urine vs oral fluid vs hair

Again, quoting from the DTI report: “In the general US workforce, marijuana positivity reached 4.4% in urine testing and significantly higher levels in alternative collection methods, including 11.1% in oral fluid and 15.1% in hair testing.”

Jason S. Hudson, PhD, Scientific Director and Laboratory Director, Workforce Solutions, for Quest Diagnostics, explains why positivity rates are higher with hair and oral fluid tests compared to urine:

"Hair testing and oral fluid testing not only capture different windows of use but are also more resistant to tampering and substitution than traditional methods. This gives employers more accurate insight into safety risks. That matters because substance use in the workplace doesn't just affect productivity; it can directly impact safety, decision-making, and the well-being of employees.”

Regarding marijuana and hair testing, the DTI reports: “Over the past five years, overall hair test positivity for marijuana increased 58.9% (9.5% in 2021 vs 15.1% in 2025). Pre-employment hair test positivity for marijuana increased 49.5% over the past five years (10.1% in 2021 vs 15.1% in 2025). Random hair test positivity for marijuana increased 14.8% in the same period (18.3% in 2021 vs 21.0% in 2025).

Additionally: “Marijuana also accounted for 52.5% of hair drug positives in 2025. By comparison, overall urine drug test positivity in the general US workforce slightly declined to 4.3% in 2025 from 4.4% in the prior year.”

As Dr. Hudson points out, the window of detection for each testing method is different and may be a key factor in determining which testing method is right for one company versus another. For instance, drugs are detectable in a urine sample about 6-7 hours following usage and for up to 3-4 days at the cutoff levels currently in use (though cannabis metabolites can remain detectable for weeks after usage). Drugs are detectable in an oral fluid sample within minutes after usage and remain detectable for about 24 hours, though it could be less depending on the testing method used.

Strategic implementation: Leveraging alternative testing for pre-employment

By comparison, drugs are detectable in a hair sample starting about 7 days after usage, but they remain detectable for up to about 90 days. Hair testing’s longer window of detection makes it ideal for pre-employment screening, especially for companies in safety-sensitive industries. For example, many trucking companies use a hair test to screen job applicants for drugs prior to conducting a DOT-required urine test. A candidate who fails the hair test, conducted by company authority and in compliance with any applicable state laws, typically would not advance to the DOT-required test.

It is also worth emphasizing that hair tests are more difficult to subvert compared to urine because the donor and collector are typically together throughout the entire collection process, eliminating many common drug-test cheating methods used to subvert urine tests.

What should employers take away from this year’s DTI?

First, that a sizeable minority of the American workforce uses drugs, principally marijuana, on a recurring or chronic basis.

Second, while traditional urine testing methods only capture drug use within a window of several hours or days, hair analysis provides a longer window of detection that may reveal a donor’s lifestyle pattern of drug use.

Third, hair testing offers unique insights into habitual drug use behaviors that, if undetected at the time of hiring, could result in putting someone in a safety-sensitive position who may be more likely to cause an accident resulting in property damage or injury.

“Utilizing different testing matrices like urine, oral fluid, and hair gives a more complete picture. Oral fluid can indicate very recent use, which is valuable for post-accident or reasonable suspicion testing, while hair testing offers a long-term history of use patterns,” Dr. Hudson said. “In the current environment, a one-size-fits-all approach is perhaps no longer sufficient. Instead, considerations regarding the employer's specific goals for their workplace drug testing program, whether that focuses on recent use, safety-sensitive matters, or broader employee support, should be taken into account when structuring their programs.”

In this age of legal marijuana, drug testing has become more important than ever. Fortunately, there are multiple testing methods available that have proven to be effective in helping employers in any situation improve and maintain safe and productive workplaces.