SANTO DOMINGO, Dominican Republic -- Letitia Vriesde of Surinam, gold medalist in the women's 800-meter run and a former Olympian, failed a doping test at the Pan American Games.

Pan American Sports Organization president Mario Vasquez Rana said Sunday that Vriesde had admitted her guilt after excessive caffeine was found in her system.

"She would have needed to drink five gallons of coffee for that level of caffeine to be found in her system,'' Vasquez Rana said.

He said that he was greatly saddened by the doping case, "especially because it involved a small country that had just one medal.''

"All of this is very painful,'' Vasquez Rana said, adding he feared there would be another positive test forthcoming.

Vriesde, 38, the defending champion who also ran at the 2000 Olympics, was her country's first Pan Ams champion when she won at Winnipeg. She's also won silver and bronze medals at the world championships.

"I don't know how we as a nation should deal with this,'' Surinam Olympic Committee chairman Gerard van Dijk said. "This comes so shortly after that moment of glory a few days ago, and to have that moment taken away like this is painful.''

Vriesde trains and lives in The Netherlands.

It was the first positive test at these games. Doping tests are being conducted by a laboratory in Canada. Traditionally, all gold medalists are tested and other athletes are checked randomly.

More than 5,000 athletes from 42 countries are participating at the games.