Hamilton appeal rejected

"CAS has confirmed the reliability of the blood transfusion test applied to Hamilton during the Tour of Spain (in September 2004)," the court said in a statement on Saturday.

The American cyclist had been under a cloud of doping suspicion since the 2004 Athens Olympics where he tested positive for a blood transfusion.

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.

A blood transfusion is considered a form of blood-doping under the World Anti-Doping Code because it allow athletes to increase their oxygen rich red blood cells, increasing their aerobic power and endurance.

Hamilton has always denied ever using any form of performance-enhancing drugs.