PARIS -- A second drug test indicates U.S. sprinter Kelli White used a stimulant during the World Championships this summer, when she won two gold medals, track's world governing body said Thursday.

The results confirmed an earlier test that found modafinil, a medication used to treat a sleep disorder, in White's urine, according to Nick Davies, a spokesman for the International Association of Athletics Federations.

The latest test was conducted on a second sample taken from White during the August meet, but not tested until now.

U.S. officials must now decide whether the case constitutes a doping offense.

The results go to USA Track & Field officials, who are expected to refer the case to the U.S. Anti-Doping Agency, Davies said. White will lose her 100- and 200-meter gold medals if U.S. officials determine she committed a doping offense.

USA Track & Field spokeswoman Jill Geer wouldn't comment Thursday other than to say the results from the second test weren't surprising.

"Remember, Kelli said the day the story broke that she was taking modafinil, so she's never said it wasn't in her system," she said.

After she tested positive for modafinil at the championships in France, White said she used the medication for a sleep disorder and didn't know it contained banned substances.

The IAAF said modafinil was covered under the category of "related substances."

If White is stripped of her medals, Torri Edwards of the United States would be awarded the 100 gold medal while Zhanna Block of Ukraine would take the silver and Chandra Sturrup of Bahamas the bronze.

The new 200 champion would be Russia's Anastaiya Kapachinskaya. Edwards would take the silver and France's Muriel Hurtis the bronze.

Also Thursday, the IAAF said a second sample from American 110-meter hurdler Chris Phillips, who finished fifth at the worlds, also tested positive for modafinil.