Tox Tuesday: Oral fluid drug testing as a roadside method

July 03, 2018

Earlier this year, the Governor’s Highway Safety Association (GHSA) released a report showing that in 2016, 44% of U.S. drivers who were killed in car crashes (with known drug tests results) had tested positive for drugs. More than half of that 44% had ingested marijuana, opioids or a combination of both.  Meanwhile, crashes involving alcohol usage went down.

The statistics mark a sharp increase in drug-related car crashes. A decade ago, just 28% of drivers killed had tested positive for drugs.

The report is evidence of how the drug scene is rapidly changing around the globe. With marijuana now legal in more parts of the world (most recently, Canada legalized recreational marijuana), and an opioid abuse crisis claiming lives every day, setting standards and regulations for drug testing becomes increasingly more like hitting a moving target.

Oral fluid drug detection is in many ways at the forefront of the discussion. Especially in the context marijuana legalization, oral fluid screening has been put forth as a viable solution for roadside drug testing. U.S. states like California and Colorado, which have both legalized recreational marijuana, have implemented pilot programs for roadside oral fluid testing. California even recently had its first driving under the influence of drugs (DUID) conviction based on oral fluid evidence, which led to the detection of methamphetamine in the blood of a driver in a fatal car crash.

Oral fluid testing was mentioned in the GHSA report. Law enforcement and traffic safety stakeholders were recommended by the GHSA to closely follow the development of new testing methods, like oral fluid devices, that could solve some of the latest conundrums faced by authorities.

Different oral fluid collection devices work differently, but overall, some of the commonly touted advantages for all oral fluid detection include:

  • Oral fluid contains many of the same analytes found in blood, as well as parent drugs that have not yet been metabolized. The presence of parent drugs is important for this matrix, because it shows the drug nearly instantly after consumption, which could be useful for proving that someone is driving under the influence. The parent drug is rapidly converted in blood to metabolites that are excreted in urine 12–24 hours later, meaning that urine tests take longer to detect drug use.

  • Because of this, oral fluid testing works just hours after the initial drug use and can even work instantly depending on the drug targets. Parent drugs can be detected immediately, and metabolites will take some time to convert within the body.

  • It practically eliminates adulteration concerns. Urine testing is well-established, and many ways of cheating have been developed, from diluting to using fake urine Oral fluid tests can be conducted under direct supervision without compromising the test taker’s privacy, preventing all of this.

  • In addition to decreasing adulteration risks, it’s more practical to perform an oral fluid screening. It’s not necessary to transport someone to a bathroom for a urine test, or a medical facility for a blood test.

Oral fluid testing is still relatively new, in the grand scheme of things, and the circumstances around drug use and testing needs are very much still in flux in many countries. More development is taking place both on the scientific research side and the legislative and regulatory side. And as drug usage continues to rise in many places, the need for solutions too will become more potent.

Category: Toxicology