The number of Hawaii workers testing positive for crystal meth, or "ice," rose to 0.9 percent of all those tested in the first quarter from 0.6 percent a year earlier, according to the latest workforce drug testing by Diagnostic Laboratory Services Inc.

Marijuana, the most commonly detected drug in the tests, also was up to 2.5 percent from 2.3 percent in the first quarter of 2014, the data shows. Opiate use was flat at 0.2 percent, while cocaine use dropped to 0.2 percent from 0.3 percent.

"I wouldn’t get too excited over that because it’s such a small number to begin with. Statistically, you could almost say it’s really about the same," said Carl Linden, DLS scientific director of toxicology. "(Drug use) is not going away. One goes up, another goes down. It’s very addictive and very harmful in terms of what it does to your behavior and in terms of your health."

Meanwhile, the use of synthetic urine, which is marketed as a way to mask drug use, more than doubled to 0.9 percent from 0.4 percent in the quarter.

"We are a little surprised to see the rising level of synthetic urine use because it dropped significantly after we found a way to detect it in 2010," Linden said. "I can only guess that there are new brands on the market, and people are believing the hype."

DLS’ quarterly sample size typically includes between 7,000 and 10,000 drug tests.

In 2012, Hawaii banned several categories of "legal" synthetic drugs, such as bath salts, which can’t be tested for in workplace drug testing, according to federal and state law. However, a physician can order tests for synthetic drugs.

DLS is a medical testing laboratory that offers a range of testing services. The company employs more than 500 people and has locations throughout Hawaii, Saipan and Guam.