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Hair, Saliva or Urine—Which Is Best for Drug-Testing Job Candidates?

A female scientist working in a laboratory.

​Employers want a safe and healthy workforce, and so two-thirds of them test workers for drug use, according to recent research—but which method of testing is most effective?

There are currently three primary methods of specimen collection:

  • Urine, which is by far the most prevalent, with 90 percent of employers using it, according to background screening firm HireRight.
  • Saliva, used by 10 percent of employers.
  • Hair, used by 7 percent of employers.

The vast majority of employers use urine testing over saliva or hair, primarily because "it's what people have always done," said Matthew Nieman, an attorney in the Washington, D.C., regional office of law firm Jackson Lewis. The typical organization looks to the Department of Transportation (DOT), which tests truck drivers and airplane pilots, and because it still uses urine testing, it's the de facto industry standard, Nieman explained.

The DOT is reportedly on the cusp of adding saliva as the second approved specimen for federal testing, in a rule due sometime this year, according to experts.

Dr. Todd Simo, HireRight's chief medical officer, noted that alternate specimens are gaining interest, especially since urine tests aren't as accurate.

"Both hair and oral fluid testing have had double-digit yearly growth as more companies become aware [of them]. And both hair and oral have substantially higher positive hit rates."

When comparing the number of people who self-report drug use to the National Institute of Drug Addiction and the number of positive test results from Quest Diagnostics nationwide lab, Simo said, urine screens don't detect as many drug users as would be expected.

But he pointed out that urine and hair testing pick up many different drugs, such as prescription medications, which get overturned when reviewed by a medical professional, while oral testing panels are typically screening only for marijuana, cocaine, PCP, amphetamines and opioids. Medical review—which determines whether a legitimate medical explanation can account for positive results reported by the lab—is an important piece of any workplace drug-testing program.

 [SHRM members-only online discussion platform: SHRM Connect]

Pros and Cons

Urine testing. Urinalysis is currently the only approved drug-testing method for workplaces covered by federal guidelines. It's easy to collect the specimen, which can be screened for many illicit drugs as well as prescription medication, said David Bell, the CEO of USA Mobile Drug Testing, a drug-testing provider in Tampa, Fla.

On the other hand, people have figured out how to cheat on the test, Simo said. "Urine as a specimen is very easily manipulated. There are literally hundreds of websites out there that sell adulterants and synthetic urine for people to buy that can subvert a urine drug testing program."

But cheating may not be that easy. Bell said that while employers typically don't observe workers while the specimen is collected, increasing the risk of tampering, "a urine screen is difficult to cheat as the temperature, pH and creatinine is checked to ensure specimen integrity. Attempts to dilute a urine specimen will only create a specimen that is inconclusive and requires a retest."

Saliva testing. Oral fluid testing can be collected immediately onsite, which makes it more efficient and reduces the amount of time and cost for collection, Bell said. "The test can detect use that has been extremely recent where urine tests require the drugs to have passed through your system to identify."

Saliva testing has a lot of appeal, Nieman agreed, "especially for employers who want to do it themselves. Testers can get FDA-approved onsite swab tests, observe the specimen collectionmaking it hard to subvertand send it off to the lab for confirmation. However, some states and localities limit or prohibit onsite testing, so employers need to be aware of the laws that apply to them."

Because of the small detection window—from a few minutes up to about 48 hours—oral tests are likely catching chronic daily users, Simo said. "These are the people you want to deter and keep off your job site because they represent the most imminent risk."

But the limited detection window is also its drawback. "It can only detect drug use that as happened within the past couple of days," Bell said.

Hair testing. Drug-testing hair is a simple and noninvasive way to detect drug use over a greater length of time, most effective when testing for regular use of drugs such as cocaine, methamphetamines and opiates. These drugs can become undetectable in urine after three to four days.

"Hair testing has the highest 'fear factor' as a deterrent," Simo said. "Employers that advertise hair testing deter drug-using applicants that just stay away. It's impossible for regular users to prepare for it."

On the other hand, it typically does not do a good job at detecting sporadic usage, he said.

And "it doesn't really cover the few days right before the test, because it takes time for hair to grow," Nieman said.

Which Method Should You Use?

Specimen collection is dependent on each organization's drug-testing needs. "The best option is what you're comfortable with," Nieman said. "If you're a small employer and comfortable with being trained on how to conduct onsite saliva testing, go for it. If you are already contracting with a lab for urine testing, you don't have to reinvent the wheel."

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