SAINT-DENIS, France -- American sprinter Kelli White insists she did nothing wrong.

White says she took medication only to treat a sleep disorder, not to enhance her performance, and had no idea it contained a banned substance.

She says she didn't bother to apply for a medical waiver or include the medication on her doping control form because it wasn't on the prohibited drug list.

That was White's defense Saturday as she came under investigation for a positive test that could cost her two gold medals from the World Championships.

"I have never taken any substance to enhance my performance," said White, who pulled out of Saturday's 400-meter relay final. "Because I know that I did nothing wrong and sought no advantage over my competitors, I am confident that things will work out in the end."

Convincing world track officials of her innocence won't be easy -- the rule book and precedent aren't on her side.

The International Association of Athletics Federations said White risks being stripped of her gold medals in the 100 and 200 meters after testing positive for the stimulant modafinil. She also could face a two-year suspension.

Under the sport's strict policy, athletes are disqualified from an event if a banned substance is found in their system -- regardless of the circumstances.

IAAF general secretary Istvan Gyulai said "at the moment all indications" point toward the matter being ruled as a doping case, which would result in White's disqualification from the championships.

In one of the most celebrated cases of its kind, Romanian teenage gymnast Andreaa Raducan was stripped of the all-around gold medal at the 2000 Sydney Olympics after testing positive for a stimulant contained in a cold pill. Olympic officials acknowledged the measure was harsh but said they had to apply the rules.

White pulled out of the women's 400-meter relay final Saturday, saying she did not want to distract her teammates. France beat the American team for the gold.

The IAAF said White was eligible to run in the relay pending a final ruling, but warned that the United States risked being disqualified later if she was confirmed guilty of a doping violation.

With Torri Edwards running anchor instead of White, Christine Arron blew past her in the final straightaway to give France the gold in 41.78 seconds. The U.S. team was second in 41.83.

IAAF officials indicated the central issue in White's case was not so much whether she should be disqualified and lose the medals but whether she also should receive a warning or a two-year suspension.

Under IAAF rules, the penalty for use of light stimulants, such as ephedrine, is disqualification and a public warning. For harder stimulants, such as amphetamines, the sanction is disqualification and a two-year ban.

IAAF vice president Arne Ljungqvist, the federation's anti-doping chief said the IAAF told USA Track & Field to hold a hearing and take any disciplinary action, with the decision subject to final approval by the world body. Ljungqvist said he doubts the case will be resolved before the end of the championships Sunday.

"It is up to the United States and usually they take some time," he said.

Asked whether there was any chance White could avoid being disqualified and lose the medals, Ljungqvist said, "It depends on the full investigation and the full report. It remains to be seen."

The IAAF confirmed a report in the French sports daily L'Equipe that White's drug sample contained modafinil, described as a "psychostimulant" that stimulates the central nervous system and is often used to fight fatigue and sleepiness.

Ljungqvist said the IAAF needs to determine whether the substance falls under the category of strong stimulants, like amphetamines, or light stimulants, like ephedrine.

Under IAAF rules, the penalty for use of light stimulants is disqualification and a public warning. For harder stimulants, the sanction is disqualification and a two-year ban.

Modafinil has also been identified as a performance-enhancing drug, Ljungqvist said.

In recent years, athletes have been warned repeatedly to refrain from using supplements or other substances that could trigger a positive test. They are told to clear all medications with team doctors.

Under IAAF rules, athletes must notify the federation in advance of any products they take for medical reasons. To apply for a medical waiver, athletes must provide records proving they need to take a substance for therapeutic reasons.

But White insisted she didn't need to do that.

"Given that it (modafinil) was not on the banned list, I think it is understandable why I didn't realize that I needed to declare it," White said.

"We thoroughly researched this," she added. "It wasn't on the banned list." Under IAAF rules, athletes must notify the federation in advance of any products they take for medical reasons.

Of White's failure to seek clearance for the drug, Ljungqvist said, "She did declare other supplements she was taking but not this particular one. Of course it is an embarrassing factor for her that she would neither declare nor get prior exemption.

"She should have done it. Even more, she should have asked for a prior exemption to use it. "

IAAF general counsel Brian Gay said the IAAF needs medical records proving White's doctor prescribed the medication.

"We haven't yet found whether her explanation holds water," he said.

White said she was diagnosed with narcolepsy this year and began taking the drug Provigil, which contains modafinil, a few months ago on the prescription of her personal doctor, Brian Goldman.

"It has improved the condition in my day-to-day life and helped me function normally," White said.

"I was extremely tired all the time, not sleeping well in the evening due to sleeping in the daytime," White said. "My memory isn't very good. I needed just to be right."

White said she had been taking the medication at the time of competitions in the United States, London and Oslo, Norway, and passed all drug tests at the time.

"I never thought that this would be a problem now," she said.

White said she used the substance the morning of Sunday's 100-meter final. She didn't say whether she also used the medication before Thursday's 200-meter race.

Pressed on why she didn't list the substance on her forms, White said: "Because it isn't a medication that I take every single day. It's on an as-needed basis, and because I took it so early in the day I never thought to list it. After a competition, it's kind of hard to remember everything you take during the day."

If White loses the medals, fellow American Torri Edwards would move up from silver to gold in the 100, and Russia's Anastaiya Kapachinskaya would be upgraded to gold in the 200.

In other revised results, Zhanna Block would get silver and Chandra Sturrup bronze in the 100, with silver for Edwards and bronze for France's Muriel Hurtis in the 200.

If disqualified, White would also lose $120,000 in prize money -- $60,000 for each gold -- and possible sponsorship bonuses.

This is not the first time that White has been involved in a disputed drug test in France.

In July 2002, after running in a meet at Saint Denis, White's sample turned up traces of a corticoid -- an anti-inflammatory steroid. She was suspended for six months by France's anti-doping agency because she lacked a medical certificate, but the IAAF cleared her of any offense.

White tried to be philosophical.

"Things happen in life," she said, "and I will just have to deal with the consequences."