Marijuana use by job seekers rose steadily during 2005 while crystal methamphetamine use dipped a little before rebounding to where it was when 2004 ended, according to statistics released yesterday by Diagnostic Laboratory Services Inc.

The private company, which is the largest drug testing firm in the state, said about 6 percent of the tests the company performed during the fourth quarter of 2005 came back positive.

Carl Linden, scientific director for the company's toxicology section, said the company averages between 8,000 and 8,500 drug screening tests per quarter. About 80 percent of the tests are pre-employment, performed on job applicants referred to the company by about 700 employers in Hawai'i, Linden said.

"The statistics are disappointing, in that the ice abuse is not decreasing and the marijuana is actually trending upward," Linden said. "Some employers are finding it harder to lure and retain drug-free employees."

Janice Okubo, a spokeswoman for the State Department of Health, said that because the data focus on pre-employment testing, it should not be taken as an accurate reflection of the entire state when it comes to drug use.

"Eight thousand to 8,500 is a large number of drug tests, which is why this could be statistically significant, but the percentage changes are very small," Okubo said, adding that the testing is not necessarily a broad-based overview of the state's population.

According to the DLS study, one out of every 50 tests for methamphetamine use were positive during the final three months of 2004, a rate that was identical for the final quarter of 2005.

Keith Kamita, administrator of the Narcotics Enforcement Division of the state Department of Public Safety, said the drug-screening results are not a surprise, nor is the finding that marijuana use rose throughout the year.

"We find most of the ice (crystal methamphetamine) users are poly users," Kamita said. "They dip into Valium ... to go to sleep and smoke marijuana to eat so they can go back to work and resume their life."

In addition, some of the increase in the number of marijuana users detected during the screening tests could be because 3,042 medical marijuana users are now registered with his office.

"That makes it easier for kids or other young adults in the same household to raid grandma's stash," Kamita said.

He said his office does not have an estimate on what percentage of the overall Hawai'i workforce uses, or is suspected of using, illicit drugs.

In the Diagnostic Laboratory testing, the positive rate for meth tests was running about 1.6 percent for the first three months of 2005; climbed to about 1.9 percent in the second quarter; dropped again to about 1.7 percent in the third quarter; and rose again during the final three months to 2 percent, according to the DLS statistics.

By comparison, the rate of positive tests for marijuana climbed steadily throughout the year. Positive tests for cocaine use dipped slightly in the third quarter but were on the rise during the final three months.

And the rate of positive tests for opiates also was on the rise during the fourth quarter of 2005, the DLS testing found.

Linden said the statistics are based on samples collected statewide. He said DLS has provided workplace drug testing services since 1980 and began releasing "quarterly trending" information early last year.

He said the rate at which crystal meth test results come back positive is much higher in Hawai'i than the Mainland averages, while the rates of positive test results for the other drugs is comparable to those on the Mainland.

He said some of those tested showed "positive indicators" for more than one type of drug use but could not say immediately how often that is the case.

Linden said that while drug use affects those in both blue- and white-collar jobs, he believes it is more prevalent among entry-level, service industry workers.

Reach David Waite at dwaite@honoluluadvertiser.com.