LONDON (Reuters) - Five suspect doping samples from the Athens 2004 Olympics that were discovered during re-testing in July involve substances that were known at the time, the International Olympic Committee on Wednesday.
The IOC said they stumbled across the adverse analytical findings during re-testing, not for substances like the blood boosting CERA that became known a few years later, but for substances that drugs testers were already aware of and testing for at the time.
"There was no information that any substance would have been in use that was not already analysed," IOC Medical Commission chief Arne Ljungqvist told an IOC meeting.
"So we said why not use new more advanced testing methods for substances that had already been analysed for but with techniques that had been developed in the last years, more sophisticated and more sensitive," he said.
"We have a few reports from the lab that are suspicious."
The IOC said earlier in July it had found five cases but did not name the athletes, awaiting the testing of 'B' samples.
"Had we done it earlier we would probably not have found much as the methods were not developed that much," Ljungqvist said in response to former anti-doping chief Dick Pound's comment that re-testing took place too late.
"We could have done it a little earlier but the earlier the less likely to have found anything," Ljungqvist said.
The IOC also re-tested samples months after the Beijing Olympics and found five positive tests for CERA, for which there was no method of detection at the time of the 2008 Games.
Editing by Greg Stutchbury