More than halfway through the Sochi Olympics, the IOC's top anti-doping official says he's not surprised there have been no positive tests so far.
Arne Ljungqvist, chairman of the IOC medical commission, says the stringent drug-testing system is working as a deterrent.
He says "it's expected that people don't cheat and those who do are not here.''
As of Friday night, Sochi organizers had conducted 1,799 tests, out of total of 2,453 planned for the games. No positive findings have been reported.
Ljungqvist noted that only one positive test was recorded at the 2010 Vancouver Games.
He says "it shows that the program is pretty efficient and serves as a deterrent.''