Landis says he did not cheat and has vowed to clear his name

Regulations limit the ratio of the male sex hormone testosterone to its shadow epitestosterone to four to one.

However, Dr Brent Kay says that the initial test on Landis showed that the ratio in the American was 11 to one.

"I've seen bodybuilders with numbers 100 to one," Kay said. "Floyd's was elevated but it's not off the chart."

The range for an average person is between one to one and two to one.

Landis faces a two-year ban and could be stripped of his title after testing positive for unusual testosterone levels after stage 17 of the race.

The 30-year-old won that stage by almost six minutes to put him back into contention for the yellow jersey.

His victory was made even more remarkable by the fact that the day before Landis had cracked on the final climb of stage 16.

The Phonak rider denies the charges, stating that he has naturally high levels of testosterone.

The result of tests on Landis' B sample will be announced on Saturday.

"It is imperative that the B test be done this week for the credibility of our sport," said International Cycling Union president Pat McQuaid.

"This needs to be put to rest because there is too much innuendo, too much talk, too much damage being done to our sport.

"We have to get this process done quickly so we can move on."