"Lance Armstrong is one of the most tested athletes in the history of sport, and he has come up clean every single time," Bisceglia said. "This kind of years-ago testing of a single sample with new technology is completely without credibility.

"What's worse is that Lance cannot defend himself because there is no mechanism for final resolution," he said.

Although Armstrong has not said if he'll pursue legal action, Bisceglia said USA Cycling will support him in whatever way he chooses to "denounce these accusations." On Thursday, Armstrong lashed out at the French lab that produced the findings.

"There's a setup here and I'm stuck in the middle of it," Armstrong told The Associated Press. "I absolutely do not trust that laboratory," he said.

Armstrong spoke after Dick Pound, head of the World Anti-Doping Agency, said officials had received the lab results and would review them.

Armstrong also said that while Pound might trust the lab that tested the samples, "I certainly don't."

Armstrong elaborated Thursday on CNN's Larry King Live .