ATHLETICS/ News: Kelli White will challenge the decision of the IAAF not to accept her explanation for failing a drugs test. The double gold medallist from the World Championships could now have both titles taken away from her.

The American won the 100 metres title at the recent championships in Paris but was then found to have tested positive for Modafinil, a substance not on the IAAF's banned list. However, the substance is regarded as "related" and belonging to the minor ephedrine family of drugs.

Last night the IAAF refused to accept the explanation of White who, after winning the 100 metres gold then landed the 200 metres title, used the prescription drug Provigil to combat narcolepsy.

IAAF spokesman Nick Davies said: "The IAAF have received the athlete's explanation regarding a positive test for Modafinil at the World Championships in Paris, but it has not been accepted.

"In accordance with the usual disciplinary procedures, under IAAF rules the matter is now referred to their member federation, USA Track and Field, to a hearing on a date to be agreed with the athlete."

Under new procedures adopted in her home country White, only the third woman to win both 100 and 200 metre crowns in the championship's 20-year history, will appear before the USA anti-doping agency. If found to have committed a doping offence, the normal IAAF sanction will be a public warning and disqualification from the Paris competition.

A guilty verdict will see White, (26), lose both her gold medals, although because of the minor nature of the offence there will be no suspension.

White's manager Robert Wagner said the athlete would be asking what could be embarrassing questions of the IAAF.

White will be asking why, despite already knowing of her "positive" test for a substance which is not on their banned list, they allowed her to compete in the longer event two days after the 100 metres success, knowing she could lose both titles.

Having earlier in the summer produced negative samples at accredited IAAF laboratories in Los Angeles, Oslo and London, White will now enquire if those tests showed illegal amounts of Modafinil. If they did White will query why no disciplinary action was taken.