The Badminton World Federation said any changes to doping rules would have to go through the World Anti-Doping Agency as banned former women's world number one Zhou Mi fights to clear her name. Hong Kong's Zhou, whose two-year suspension began in August last year, gave a press conference in the Chinese territory on Thursday to reiterate she was innocent of doping and unaware of consuming any prohibited substance. The South China Morning Post reported that Zhou is calling for a review of how cases involving the drug clenbuterol, for which she tested positive, are handled. "I would like to make an appeal to all sporting governing bodies to reconsider clenbuterol as a strictly banned substance -- especially when test samples show very low concentrations of the drug," she said. Zhou reportedly said she would not appeal her ban because the deadline had passed. But BWF chief operating officer Thomas Lund said Saturday that any revision to clenbuterol testing would have to come through the World Anti-Doping Agency (WADA). "It's a very technical issue.... We are following the rules and regulations for all sports," he told AFP. Clenbuterol, though banned in China, has been found in contaminated pork. It is an additive that can speed up muscle building and fat burning to produce leaner meat. Lund said the sport's global governing body could not lift the ban. "It's not in the power of the BWF to lift the suspension. The case has been dealt with by an independent hearing panel. They came to a conclusion that there was a suspension needed." "Of course it's always unfortunate when these cases come up," he added.