Kelli White, who has tested positive for a stimulant which is not listed by name as a banned substance, insists she should be allowed to keep the gold medals which she won in the 100 metres and 200 metres at the World Championships.

The American tested positive for modafinil after her 100m triumph last Sunday and the IAAF have said that she may end up having to give back her medals - even though the substance is not on their list of banned drugs.

The IAAF said it was covered under a clause for "related substances" and are looking into whether modafinil may fall under the category of ephedrine, a minor stimulant, or a strong stimulant like amphetamines.

If it is classified as the latter, White could be facing a ban as well as being stripped of her medals.

White defended herself vigorously at a press conference in Paris tonight, revealing that she takes the drug Provigil because she has narcolepsy.

The drug contains modafinil.

"I am under suspicion of a doping violation," said the 26-year-old White.

"The mere fact of this allegation is personally harmful and hurtful.

"Honestly, deep in my heart I know I'm innocent.

"I would take full responsibility but the medication is not on the banned list.

"I have never taken any substance to enhance my performance.

"Close members of my family have been under doctors' care for the condition of narcolepsy for years.

"I, too, have been diagnosed with this condition by my physician, Dr Brian Goldman. He prescribed the drug Provigil for this condition and I have taken it in certain circumstances, including prior to the 100 metres."

Explaining why she had not declared it before the championships in accordance with IAAF rules, White said: "I did not seek IAAF medical exemption for this substance or note it on my doping control form, because I had no idea Provigil contained a banned substance.

"Neither Provigil nor the substance in Provigil identified (modafinil acide) by the IAAF, are on any lists of banned substances.

"I treat these matters very carefully - for example, I have carefully and consistently noted other substances used to treat injuries on my doping control form."