Trinidad and Tobago sprinter Kelly-Ann Baptiste, who won a world 100m bronze medal in 2011 and was a real prospect for Moscow, has tested positive for a banned substance, the Trinidad Express newspaper reported on Saturday.

Baptiste, 26, has returned home from the world championships where she was due to run in the first round of the 100m heats on Sunday morning.

"She has voluntarily withdrawn from the competition and is heading back to her base," the newspaper quoted Trinidad and Tobago team manager Dexter Voisin as saying.