The Portuguese long distance runner Helder Ornelas has been banned for four years by his country's federation after becoming the first athlete to be found guilty of doping using the Athlete Biological Passport.
The IAAF president Lamine Diack says the suspension of the 38-year-old, who ran the 5,000m at the Sydney Olympics and the marathon in Beijing, marks a breakthrough in the fight against doping.
The IAAF did not reveal what the banned substance was but said blood samples from Ornelas has been collected in the course of the Biological Passport programme during a 11-month period from December 2009.
Ornelas's blood profile was flagged as being abnormal in May 2011, triggering further investigations in accordance with IAAF Anti-Doping Regulations.
The Athlete Biological Passport will be used for the first time at an Olympics in London this year.