Drug use by the U.S. workforce remains at its highest level in more than a decade; the positivity rate for drug tests in 2017 was 4.2 percent, the same as in 2016 and the highest since 2004, according to the 2018 Quest Diagnostics Drug Testing Index.

The analysis of 2017 data suggests shifting patterns of drug use, with cocaine and amphetamines positivity surging in some areas of the county and marijuana positivity rising sharply in states with newer recreational use statutes. Prescription opiate positivity rates declined dramatically on a national basis.

“It’s unfortunate that we mark 30 years of the Drug-Free Workplace Act with clear evidence that drugs continue to invade the country’s workplaces. Not only have declines appeared to have bottomed out, but also in some drug classes and areas of the country drug positivity rates are increasing,” said Barry Sample, PhD, senior director, science and technology, Quest Diagnostics. “These changing patterns and geographical variations may challenge the ability of employers to anticipate the ‘drug of choice’ for their workforce or where to best focus their drug prevention efforts to ensure a safe and healthy work environment.”

In urine testing, the positivity rate for cocaine increased seven percent in the general U.S. workforce (0.28 percent in 2016 vs. 0.31 percent in 2017). Double-digit year-over-year increases in at least four of the past five years were seen in Nebraska, Idaho, Washington, Nevada, Maryland and Wisconsin.

In the Midwest and South, methamphetamine positivity skyrocketed – 167 percent in the East North Central division of the Midwest (Illinois, Indiana, Michigan, Ohio and Wisconsin).

“Thirty years in, this year’s results again demonstrate the ever-evolving threat that substance abuse poses to workplace safety. With the prescription opiate crisis filling the headlines, the significant drop in opiate positivity is a promising sign,” said Matt Nieman, General Counsel, Institute for a DrugFree Workplace and Principal, Jackson Lewis P.C. “Yet, the ten-year high in positivity rates—spurred by nationwide surges in cocaine and methamphetamine positivity as well as double-digit marijuana spikes in states with newly implemented recreational laws—serves as a stark warning that efforts to prevent substance abuse in the workplace are as important today as ever.”