Cycling: Lance Armstrong's vehement defence of his reputation in the face of this week's doping allegations continued yesterday as he questioned the procedures which appear to indicate he tested positive for the blood booster erythropoietin (EPO) six times during the 1999 Tour de France, the first of his record seven victories.

Appearing on the Larry King show on CNN, Armstrong attacked the procedure that led to news of the apparent positive tests being leaked to the newspaper L'Equipe.

The samples were analysed as part of a research programme to refine the current test for EPO, which came into use at the Sydney Olympics in 2000.

"No protocol was followed," said Armstrong, "and then you get a phone call from a newspaper that says: 'We found you to be positive six times for EPO.' Since when did newspapers start governing sports? When does a newspaper decide they're going to govern and sanction athletes? That's not the way it works."

Later Armstrong added: "Who opened the samples? What protocol was followed? Nothing. It was all thrown out the door. We can't build trust in an anti-doping fight if we don't have faith in it."

Armstrong repeated his contention that when he delivered the samples during the race, there was no EPO in them, and hinted that they may have been tampered with, saying that now he has retired "I don't have to worry any more about giving a urine sample that will be manipulated."

However, the head of the Paris anti-doping lab which carried out the analyses, Professor Jacques de Ceaurriz, has stood by his test. He said: "We have no doubt about the validity of the results. EPO is a protein, and it either breaks down over time and becomes undetectable, or it remains as it is."

Armstrong did, however, appear to back down from his threats to add legal action against L'Equipe to his cases against the Sunday Times and French publisher La Martiniere. He said: "I'm taking this a little easier than some allegations because I'm now retired so I don't have to worry about going back and dealing with these people."

The Texan, a cancer survivor deeply involved in working with others suffering from the disease, said he had better things to do with his money than indulge in another costly court battle.

Armstrong is currently involved in a legal case against a Texas insurance company who have refused to pay him bonuses he was entitled to after his 2002, 2003 and 2004 Tour victories after arguing the legitimacy of the wins could be questioned.