Hawaii workers testing positive for marijuana dropped 7 percent in 2013 compared with the previous year, new data from Diagnostic Laboratory Services Inc. show.

The use of marijuana, known locally as paka­lolo, fell 11.5 percent year-over-year in the fourth quarter.

The drug-testing company said meth­am­pheta­mine use also declined 11 percent year-over-year in the quarter, but the entire year was essentially flat compared with 2012. Cocaine and opiate use also remained about the same over the past year.

"Definitely we’re not seeing a big surge (in drug usage). It’s either flat or dropping," said Carl Linden, DLS’ scientific director of toxicology. "Nothing’s going up, which is good. The most dramatic change was in the use of synthetic urine, which dropped precipitously by 30 percent from last year."

The use of synthetic urine to mask drug use in tests has been dropping since the laboratory started using a new detection method in 2010. Samples that do not contain drugs, but show that synthetic urine was used, are deemed invalid and require new samples.

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