Four Common Myths about Drug Testing

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When it comes to employment drug testing, there are several common misunderstandings and misconceptions, both for companies and individuals. Here we will examine some of the most prevalent myths.

Illicit drug use doesn’t impact work safety
Studies show that drug use directly contributes to an unsafe work environment. Alcohol and drugs are responsible for one in six on-the-job fatalities. According to the National Safety Council, 80% of those injured in “serious” drug-related accidents at work are not the drug-abusing employee, but innocent co-workers and others. Employees who abuse alcohol or drugs are 3.5 times more likely to be involved in a workplace accident than other workers.

These stats have been borne out in real-world examples as well. One prominent study involved the Southern Pacific Railroad and compared its accident rates before and after implementing a drug testing program. The company realized a dramatic 71.2% decrease in accidents after it began its drug testing program.

Once you use marijuana, it stays “trapped” in your body for detection on drug screens for months or years
There’s been a great deal of misinformation floating around about how long marijuana stays in the system, with some guidance stating days and some claiming it can stay in the body for years.

Recent studies have shown that, depending on the cannabis concentration being used, it’s likely that a chronic user would produce a positive urine test for less than 7 days and only in very extraordinary circumstances for about 10-21 days after the last smoking episode and an occasional user would test positive within 3-7 days after the last usage.

There’s no way to beat a drug test
There are numerous suggestions and resources available online for ways to beat the test and subvert results. They generally fall into three categories:

  1. Diluting agents: since all drug tests are predicated on concentration of the illicit substance in the body, anything that dilutes the specimen affords a greater chance to pass the test. To subvert urine drug tests, individuals sometimes try drinking copious amounts of water, fruit juice, vitamin C, or may add water or other agent to the sample.
  2. Substituting agents: freeze-dried urine and synthetic urine are available for purchase.
  3. Oxidizing agents: substances that oxidize the urine by breaking up the detectable metabolite, such as nitrite or glutaraldehyde.

Drug tests yield “false positive” results
This is based in a certain amount of fact – it’s possible that occasionally certain substances such as prescription drugs and poppy seeds can yield true laboratory positive drug test results.

However, this issue is mitigated by industry best practice to have positives be validated by evaluation by a medical review officer. The medical review officer reviews the positive result with the individual, and if the person has a verifiable, reasonable, medical explanation for the result, the report to the company would be a negative drug screen.

The misinformation about false positive drug screens found on the internet relates to initial screening data (immunoassay testing), which is very sensitive, but non-specific. This sensitivity can cause a specimen to screen positive for a drug even though there is really no presence of the drug in the specimen (i.e., the false positive).

However, all accredited labs and credible drug screening administrators use a chromatographic – mass spectrometry confirmation test to confirm all positive immunoassay results. This type of confirmation testing yields true laboratory positive results without any concern for false positives.

When reviewing the evidence these common drug testing myths and widely held misconceptions can truly be busted!

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Dr. Todd Simo

Dr. Simo is the Chief Medical Officer and the Managing Director of Transportation at HireRight. He served as HireRight’s Medical Director starting in 2009 and was promoted to Chief Medical Officer in 2015. Dr. Simo was also appointed to the role of Managing Director of Transportation in 2018. Dr. Simo came to HireRight with a decade of experience in the medical consulting arena. Before that he was Medical Director at an occupational health clinic in Virginia and owned a consulting firm providing medical director services to employers across the United States.

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