Comparison of different drug testing methods for the transportation industry

To compare the detection windows of drug testing methods, marijuana detection is a helpful common factor. Marijuana is becoming increasingly popular and is the leading reason for positive Clearinghouse drug tests.

The traditional drug test is a urine test or urinalysis. Numerous labs are certified to perform urine tests. According to Quest Diagnostics, urine tests can detect marijuana use within one to 30 days.

Oral fluid tests have a shorter detection window and are poised to become the first federally approved alternative to urinalysis. The Department of Transportation officially approved oral fluid tests in June 2023. According to Quest Diagnostics, oral fluid tests can detect marijuana use within 24 hours of consumption.

Hair tests have the longest detection window. The transport industry has been waiting for this method for a long time.

Hair tests are “promising” in detecting drug use, says Mark Savage, chairman of the American Trucking Associations’ Law Enforcement Advisory Board.

See also: Transport industry and law enforcement agencies seek common ground

“The hair tests are more accurate over a longer period of time, so your window of opportunity is larger. From the Department of Transport’s perspective, that is particularly valuable,” Savage told FleetOwner. “It [Marijuana] may not be present in their system if they have to do a urinalysis 35 days after smoking marijuana. However, it may be present for up to 90 days in hair follicle tests.”

Hair tests can detect marijuana use within one to three months, according to Quest Diagnostics. This longer time window offers the best chance of determining whether a driver has used marijuana in the past.

The sample collection itself is another critical factor in these drug testing options. Some sample collections require more effort than others.

“With urinalysis and blood tests, the collection is a little more complex,” Savage explained. “You need a facility where the urine can be collected and it can be a little difficult to get someone there and do the test, whereas with hair follicle testing, you're actually only collecting a portion of the sample.”

Hair tests are very useful due to the largest detection window and a relatively non-invasive sampling procedure.

Many trucking companies, like Schneider (No. 6 in the 2024 FleetOwner 500), use their own drug testing protocols to screen drivers in addition to the DOT-mandated tests. Among large trucking companies, hair follicle testing is a popular approach.

Why are urine tests still the only method for DOT?

Urine testing remains the only real testing method for compliance with DOT regulations. Hair and oral fluid testing both appear to be on track for federal implementation, but face unique institutional roadblocks from the Department of Health.

The examination of oral fluids has a problem with certification by a federal laboratory. After approval In a final rule in mid-2023, the DOT will technically accept both urine and oral fluid tests, but for employers to use oral fluid tests, HHS must certify at least two labs. According to Safety and Health MagazineNo laboratory is yet certified to conduct drug tests in saliva.

Hair testing lacks important federal guidelines. It took nine years of waiting for HHS guidelines before the method could move closer to DOT approval. The federal government first directed HHS to develop hair testing guidelines for DOT drug testing in 2015.

The HHS issued some guidance on hair testing in 2020, but with the stipulation that it must be followed by a urine test. Lawmakers continue to pressure the HHS to establish guidance on the use of hair testing as an alternative testing method for the transportation industry.