ROME, June 14 (Xinhua) -- World Anti-Doping Agency lab experts may change its rules regarding clenbuterol on their meeting next week.

Clenbuterol is the drug that cyclist Alberto Contador tested positive for at last year's Tour de France.

Contador blamed the contaminated meat he ate and was cleared by the Spanish cycling federation earlier this year. WADA and the International Cycling Federation made an appeal to the Court of Arbitration for Sport and it will be heard in August.

Olivier Rabin, a WADA science director, said the meeting in Montreal next week could lead to the installment of a fixed level of clenbuterol over which no excuses are valid.