SAN ANTONIO -- The owner of a drug testing lab accused of producing false positive tests in Bexar County probationees is disputing those claims and crediting the lab's more aggressive testing methods with the jump in positive tests.

Jeff Warner, the owner of Treatment Associates, said a test used before a February switch wasn't aggressive enough, and has led to a 35 percent jump in positive drug tests. He said the county's probation department was using an outdated test and an unguarded urine specimen process.

"I think that's why the rate quadrupled in the first 45 days," he said.

The company charges probationers $6 for each test and Warner said 25 percent of its tests are coming back positive.

"You're gonna be watched and the test is not beatable," he said.

On Monday, the president of the Central Texas Association of Public Employees and a Bexar County probation officer said the high numbers of positives were alarming.

"Confirmation has come back to the department and we're concerned about those, and also, a lot of defendants on their own have gone out and had hair follicle tests in other labs to confirm their suspicions," Sheri Simonelli said.

Warner said his company's test are 99.97 percent accurate, indicating drug byproducts at the moment of testing. Warner also said his company's critics do not know what they are talking about.

"They do not know, and if they do know, they haven't talked to me," he said.

For further quality control, Warner said his company will run parallel tests as well as taking other measures. Probation officers are also subject to random drug testing, but a department spokesperson said they've not been tested by Treatment Associates.