Cheating on Drug Tests? How common?

There are multiple sources that will report on the positivity rate for drug testing in the US. The combined US workforce rate held steady at 4.2% in 2017 (the same as 2016) but that is still up from the 3.5% positivity rate in 2012, the lowest in 30 years.

We perform a variety of testing in our offices, DOT testing, random monthly / quarterly testing for private companies and spot testing for companies that request it. For companies that test regularly, the 4.2% rate looks correct. If we conduct random testing for a company that has never tested or has not tested in a long time, the rate is much, much higher - normally over 25%. Why such a difference?

First, an example from one client that is no longer testing. This client had us come on site and perform 5 panel pre-employment tests every week in multiple locations. Most were in Texas (Dallas / Fort Worth / Houston) but also out of state at several locations as well. When we first started testing for them, they allowed for their candidates to test positive for THC (marijuana) and continue their training program with the understanding they would have to pass another test within 30 days.

Since there was a "grace period" for THC and we used instant result UA tests (iCup), our field technicians would inform the candidates on the spot and advise them that they should wait 30 days since their last usage before they undertook another test. We received very honest feedback from the candidates and the vast majority would confirm their positive results. The positivity rate for this company was 26.2% for the over 1000 tests we performed for them. That is not a typo - the positivity rate was 26.2%.

After using the same system of allowing for a "grace period" on THC positives for over 2 years, the company policy changed so any positive would disqualify any new candidate from employment. What did not change was these prospective employees were still told when they would be tested during their new hire orientation week. The positivity rate went from 26.2% to little over 10%. Their hiring process and their recruitment process did not change. While some candidates may have left the process early when they knew they would be required to pass a drug test that week, their recruitment numbers did not seem to change. The failure rate (a little over 10%) did include those that were found to have attempted to cheat the test. Given the parameters of their testing program (non-observed UA testing, advance warning of their drug test time and date and other factors), our team concluded the decrease in positivity (almost 16.2%) could have been the result of cheating.

For more information please see:

1) http://www.questdiagnostics.com/home/physicians/health-trends/drug-testing.html