The world's fastest man Usain Bolt could lose some gold after Jamaican teammate in the 4x100m Nesta Carter's 'A' sample tested positive for the banned substance Methylhexanamine. The report from Reuters comes after the retesting of 454 samples from the 2008 Games. Carter ran the first leg of the 4x100m relay in Beijing, which also included Michael Frater, Asafa Powell and Bolt. The quartet set a then record time of 37.10 seconds.