The hearing is to decide whether or not jockey Patrick Valenzuela was in violation of his conditional license when he failed to provide hair for a mandatory hair follicle test when he reported to ride at Hollywood Park on July 2.

Valenzuela was summarily suspended and hasn't ridden since.

Forensic toxicologist Dan Berkabile was again called as a witness and testified for nearly 30 minutes on issues such as beating a urinalysis test. He said it can be done by ingesting substances to dilute the presence of illegal drugs or by inserting items into the actual sample before it's tested.

"There's a certain percentage of sophistication out there that can beat the test," Berkabile said. "There are things out there that will help (people) beat a test. I myself could beat a urine test.

"It takes about a microliter, which I equate to about a fifth of a drop, to alter a test. Even if a person is testing in front of someone, all it would take would be something under a fingernail to alter the test or something else ingested an hour or so before being tested.

"Five percent (who beat drug tests) is a liberal estimate; three percent would be more accurate."

Berkabile admitted, however, that someone who tests hundreds of times, like Valenzuela must under the terms of his conditional license, would have a hard time consistently beating the test and would more than likely eventually be caught. Since signing his conditional license in 2001, Valenzuela has yet to produce a positive urinalysis for drugs.