Behind the Perth Cup glamour on New Year's Day, collection officers will be taking horse blood samples and whistling to get urine in the bid to keep racing honest.
About 60 control samples from the meet will be tested for performance enhancers such as illegal stimulants, steroids and EPO.
Racing and Wagering WA veterinarian Judith Medd, who oversees thoroughbred testing, said blood samples were collected before all big races to test for elevated carbon dioxide levels that could result from trainers giving horses a banned bicarbonate of soda blend, a practice known as "milkshaking".
Urine samples were also taken from winning horses - a process that could require patience.
Collection officers whistle when the horses give a sample to condition them to do the same next time.
Dr Medd said even therapeutic drugs such as anti-inflammatories were not allowed on race day.
In the last annual reporting period, 9028 doping tests were done across thoroughbred, harness and greyhound racing in WA.
The Australian Sports Anti-Doping Authority did 7196 tests in 2011-2012.
Swabs are packed in security bags to go to the ChemCentre for analysis by seven full-time staff.
ChemCentre acting manager of the racing chemistry laboratory James White said urine samples gave a lot of information.
Blood tests were typically a snapshot but urine gave coverage over time of what may have collected in the horse.
Mr White said samples were first run through broad tests, then more specific tests if necessary. "Once we've done that first screen, we'll often know whether there's nothing to be concerned about," he said.
If a banned substance is indicated, the laboratory runs accurate tests to confirm the presence of the drug for an industry inquiry.
If a complaint is received, the investigation is handed by Racing and Wagering WA principal investigator Phil O'Reilly, a former police officer who has spent the past 14 years as the "town copper" of racing.
He also assigns guards to each horse from 5am on race days and acts as prosecutor at stewards' inquiries.
He said a lot went on behind the scenes in racing to ensure horses and jockeys raced drug- free and racing maintained its integrity.