Vehicles transporting athletes'  urine samples are accompanied by armed guards as they make deliveries at the Olympic drug testing center.

The urine testing laboratory is equipped with two huge mirrors.

The Executive Board of the International Olympic Committee announced on Sunday that Greek sprinter Ekaterina Thanou had been barred from the current Games as a result of his evasion of a drug test before the 2004 Games at Athens.

The fact is that the doping issue has cast its shadow over professional sports since the profile of athletics first began to grow. With increasing efforts to eradicate drug cheats, drug testing has evolved into a "cat-and-mouse" game between the drug dopers and the drug detectors. According to the Beijing Olympic Organizing Committee, the current Games will institute the most rigorous drug-testing program in Olympic history to try to ensure a clean arena.

Doctor Li, from the Peking Union Medical College Hospital, plays the role of "cat" in the game.

Li said that in 2007, together with other four colleagues, he was chosen as a drug tester for the 2008 Games in a voluntary capacity.

One month before the Opening Ceremony, Li began to work in the drug testing center installed in the Olympic Village. The daily routine revolves around the center, the contest site and his hotel, and leaves little time for socializing.

"Don't ask me for any more details on myself," he requested, in an interview with the Beijing Times, having been instructed not to give any information about himself other than his identity as a tester.

The testers will carry out numerous tests on the top athletes in the world.

"In dealing with these people, we are under enormous pressure – there is a tendency to be overawed that could lead to mistakes," he said. "But as anonymous testers, we should be neither too haughty nor too humble in our relations with them."

Spot checks are an essential element of the drug-testing process. Athletes who fail to comply with testing procedures, risk seeing all of their achievements excised from the record books.

"The athletes I have tested have all been very cooperative," said Li.

He added that the testers are also responsible for guaranteeing that the testing itself is executed in a clean and honest fashion.

"It is forbidden for us to accept gifts or offers that might influence our work – taking a photo of a tester together with the tested athlete, asking for an autograph, or exchanging items with the tested athlete during the testing is taboo," he said.

In order to avoid corruption in the testing process, the testers are under an obligation to follow standard procedures in all activities involving sample collection, storage and filing.

"Only in this way can we minimize the possibility of cheating by those athletes who try to get away with drug use through taking advantage of loopholes in our work," he said.

(China.org.cn by He Shan, August 11, 2008)