American cyclist Tyler Hamilton, the Olympic time trial gold medallist got a two-year ban after testing positive for a blood transfusion, the United States Anti-Doping Agency (USADA) announced on Monday.

Hamilton, who received the maximum ban for a first-time doping offence, has 20 days in which to appeal to the Court of Arbitration for Sport in Lausanne, Switzerland.

He tested positive at the Tour of Spainlast September and all his results since then are forfeited.

It is the first time USADA has suspended an athlete for the presence of transfused blood.

Hamilton had been under a cloud of doping suspicion since the Athens Olympics, where he tested positive for a blood transfusion on August 18.

However, Hamilton was allowed to keep his gold medal when a second, or 'B', test was "non-conclusive" because it had been destroyed by being deep-frozen.

Blood transfusions are considered a form of blood-doping under the World Anti-Doping Code because it allows an athlete to increase their oxygen rich red blood cells, increasing their aerobic power and endurance.

Source: Xinhua