But a bigger issue for Landis figures to be another, less publicized test that has quietly gained legitimacy in recent years. It is called a carbon isotope ratio, or CIR, and it differentiates between testosterone produced naturally inside the body and pharmaceutical testosterone introduced externally.

“It's a wonderful tool,” said Catlin, the UCLA scientist who was instrumental in developing it. “We've never known it to be wrong. We use it all the time now. If you have a high t/e ratio in our lab, we do a carbon isotope ratio right away. We don't report a high t/e ratio without a carbon isotope test.”

Therein, perhaps, lies the greatest obstacle for Landis.

The Paris lab conducting tests from the Tour de France is accredited by the World Anti-Doping Agency, and WADA protocol calls for a CIR if a urine test shows an elevated t/e ratio. It also recommends that an athlete's t/e ratios from previous drug tests be examined to determine if the elevated t/e ratio is an abnormality.

The idea is that a doping case is not initiated against an athlete without at least two and ideally all three of these elements.

The International Cycling Union (UCI) did not reveal details of the preliminary lab results, and Phonak, Landis' Swiss-based team, said only that UCI notified it of “an unusual level of testosterone/epitestosterone.” But there were reports in France that the Paris lab had indeed conducted a CIR and that it was positive, and Catlin said he'd be surprised if the lab didn't perform one.

“They are a WADA-accredited lab and they follow WADA protocol,” Catlin said. “I think it's a very safe assumption – very safe. Why would they risk not doing that? I mean, good grief, you'd think they are going to have all their ducks in order for a case like this.”

And if those three elements all point to illicit use of testosterone?

“You are not going to lose the (doping) case, period,” Catlin said.