Up to five samples from the Athens 2004 Olympic Games have been found to be suspicious following retroactive testing by the International Olympic Committee (IOC).
One hundred samples were re-tested in May following a request by the World Anti-Doping Agency (WADA) using newer testing methods. It is not the first time the IOC has re-tested samples belatedly. It did so for the 2006 Turin Winter Olympics and the 2008 Beijing Summer Olympics. While no new positives were detected from the 2006 Olympics, five athletes tested positive for EPO CERA in the 2008 re-testing.
It is standard procedure for Olympic doping samples to be stored for eight years. The Athens storage period will expire on August 29, 2012.
Six medallists, out of a record 26 positive doping cases, have already been caught from the 2004 Olympic Games out of a total of 3,600 tests that were performed during those Olympics.
At present the test results are known to have "adverse analytical findings" and won't be declared as official positives until a decision is made to test B samples.
IOC medical commission chairman Arne Ljungqvist declined to name either the sports or athletes from where the samples were provided for legal reasons.
"It is a matter of less than five," he told the Associated Press. "They are potentially positive. It could be one or two, it could be none. It depends on confirmation and evaluation."
Over the next few days, investigations will reveal whether the "adverse analytical findings" were due to medications that had been allowed under a therapeutic use exemption and also whether the samples had followed a correct chain of custody.
"I had not expected it really, I must confess," Ljungqvist said. "The methods were good already and the analysis was good at the time but, of course, we are where we are. I don't know what the final result will be either — if it will be anything, or one or two or three."