The number of Hawaii workers testing positive for cocaine use has steadily increased from a year ago, according to data released Thursday by Diagnostic Laboratory Services Inc.

"Cocaine use has been slowly creeping up every quarter since the third quarter of last year, confirming what we are hearing anecdotally," Carl Linden, DLS’ scientific director of toxicology, said in a press release. "The actual number of positive tests for coke is still relatively small, but it is a definite trend."

The number of workers testing positive for cocaine grew to 0.4 percent of all those tested in the second quarter, up from 0.2 percent in the year-earlier period.

DLS’ quarterly sample size typically includes between 7,000 and 10,000 drug tests for Hawaii workers and job applicants.

Amphetamine use also rose to 0.9 percent in the quarter from 0.6 percent a year earlier, while positive tests for marijuana dropped to 2.2 percent from 3 percent and synthetic urine to 0.4 percent from 0.8 percent. Opiate use remained unchanged at 0.2 percent.

"It usually has to do with availability and cost and whatever is popular," Linden added. "It’s probably not an organic increase in cocaine users. Generally you have the same pool that’s abusing drugs, and they’re just kind of switching around to what’s hot, what’s available and what’s cheap."

The company does not test for prescription or synthetic drugs unless directed by a physician. In 2012, Hawaii banned several categories of "legal" synthetic drugs, such as bath salts, though federal and state law prohibits workplace drug testing for these substances, DLS said.

DLS employs more than 500 workers at more than 50 locations throughout the islands, as well as on Saipan and Guam.