Crystal methamphetamine use in the workplace rose slightly over the previous year in the third quarter, according to the latest drug-testing data released Friday.

Honolulu-based Diagnostic Laboratory Services Inc., which tested more than 7,000 job applicants and workers in the quarter, said amphetamine was detected in 0.8 percent of the tests, compared with 0.7 percent in the year-earlier period.

However, other workplace drug use appears to be on the decline. Opiate use dropped to 0.1 percent from 0.2 percent; cocaine to 0.2 percent from 0.3 percent; and marijuana to 2.5 percent from 3 percent. In addition, the use of synthetic urine used to conceal drug use fell to 0.8 percent from 1.4 percent.

"None of them I would be too concerned about, except crystal meth has gone from 0.5 to 0.6 to 0.8 (over the past three quarters) so that’s something to watch," said Carl Linden, scientific director of toxicology at Diagnostic Laboratory Services. "If it continues every quarter and keeps going up, it would be more alarming, but I wouldn’t get too excited about it at this point."

The use of synthetic urine, which can be bought online, heated before a drug test and kept warm with a hand-warming pack, has seen a "fairly steady decline," which was expected as word spread that employers are testing for it, Linden added.