A blood test revealed increased levels of EPO -- a hormone that encourages production of red blood cells -- said the South African Institute for Drug-Free Sport chief executive officer, Khalid Galant, the (South African) Mail & Guardian Online reported Tuesday.
George has represented South Africa in three Olympics and is one of the nation's most decorated cyclists. He was on Armstrong's U.S. Postal Service team in 1999 and 2000 when Armstrong won the Tour de France.
Armstrong was recently stripped of all seven of his tour titles after he declined to defend himself against U.S. Anti-Doping Agency allegations he used banned substances.
George and his Team 360Life cycling team have been suspended from competition pending a hearing with the South African anti-doping agency.