For the second year in a row, the percentage of American workers testing positive for illegal drugs has increased, according to a recent study conducted by Quest Diagnostics. Quest Diagnostics’ Drug Testing Index (“DTI”) – an annual analysis of workplace drug testing trends – analyzed the results of over 7.7 million urine, saliva and hair drug tests taken by employees nationwide during 2014.

The number of employees in the general workforce testing positive for illegal drug use increased in 2014 to 4.7%, up 9.3% from the year prior.  This is the second year in a row that the employee positivity rate has increased.  Prior to 2013, DTI had shown a decade’s-long decline in employees’ use of illegal drugs.  The increase in 2013 was driven largely by a 20% jump in the number of employees testing positive for marijuana use in Colorado and Washington.  Recreational marijuana laws in both states went into effect that year.

As in 2013, the 2014 increase is attributable primarily to an uptick in employees testing positive for marijuana – up 14.3% from the year prior (to 2.4%).  Unlike 2013, however, the increase in marijuana positivity in Colorado (14%) and Washington (16%) is roughly parallel to the nationwide average, surprising some drug testing experts.

While marijuana remains the most commonly detected illegal drug, the number of employees testing positive for cocaine, methamphetamines and heroin also increased, specifically:

  • Cocaine positivity was up 9.1% from 2013 in urine tests, 30.6% in oral fluid tests and 13.0% in hair tests.
  • Positive tests for amphetamines increased by 7.2% over 2013.
  • Methamphetamine positivity increased 21.4% over 2013 in urine tests, and 37.5% in oral fluid tests. The positivity rate for methamphetamines is now at the highest level since 2007.
  • The positivity rate for 6-acetylmorphine, a specific marker for heroin, doubled between 2011 and 2014.

The entire report may be accessed at