HONOLULU (AP) - An increasing number of workers who take pre-employment drug tests in Hawaii came up positive for marijuana during the last three months of 2010, according to a testing company.
About 3.5 percent of the workers tested during the fourth quarter of 2010 had used marijuana, up from 2.7 percent in the same quarter of the previous year, Diagnostic Laboratory Services Inc. said.
The increase represents a 30 percent increase over a quarter that typically has a sample size of between 7,000 and 10,000 tests, according to a Friday story from the Honolulu Star-Advertiser.
Carl Linden, scientific director for toxicology for DLS, said he didn't know what caused the jump in positive results.
The number of marijuana users is likely much higher in reality because many job seekers abstain from drugs if they know they'll be tested, he said. He estimated between 10 and 20 percent of the general population would test positive for substance abuse.
The number testing positive was ''probably the highest'' in the last decade, Linden said.
Rates of opiate and amphetamines use remained steady, at 0.2 percent and 1 percent, respectively.
Cocaine use was up to 0.3 percent from 0.2 percent in the same quarter the previous year.
DLS also found that 2.3 percent of those tested were found to be using synthetic urine, which is sold online in an attempt to fool drug tests, Linden said. DLS began testing for synthetic urine last year.
Overall, 7.3 percent of those tested in the fourth quarter were either positive for drugs or synthetic urine.