From Over at MMAJunkie.com:
"The World Anti-Doping Agency (WADA) raised the threshold for a positive test for marijuana from 15 nanograms per milliliter to 150 nanograms per milliliter, significantly reducing the likelihood of detection for athletes who use the drug.
“We wanted to focus on the athletes that abuse the substance in competition,” said Julie Masse, WADA’s director of communications. “This should exclude cases where marijuana is not used in competition.”
Although marijuana is not considered a performance-enhancing drug, WADA included it on its initial list of prohibited substances in 2003 after caving in to pressure from U.S. sports officials."