BUENOS AIRES, Argentina -- Mariano Carrera tested positive for a banned substance after winning the WBA middleweight title on Dec. 2, but the Argentine boxer is emphatically proclaiming his innocence.
The World Boxing Association announced this week that Carrera tested positive for Clembuterol, after he defeated Spaniard Javier Castillejo for the middleweight title in Berlin.
The WBA, which tested Carrera's A sample in Germany, still is awaiting confirmation of the positive result with his B sample.
Under WBA rules, the second test has to be made in a neutral country, and by a different lab.
Although the fight happened more than a month ago, WBA executive vice president, Gilberto Jesus Mendoza, said the letter with the test results was sent by the lab from Germany on Dec. 20, but arrived officially on Jan. 8.
"We have been notified by the University of Colonia's lab that boxer Mariano Carrera has tested positive in the drug test and we have verified it with the urine proof," Mendoza told ESPNdeportes.com.
Carrera's agent said that his client maintains that he didn't use any banned substances.
"Mariano assures he didn't take anything and I believe him. We are following the case closely," Mario Margossian, Carrera's agent, told ESPNdeportes.com.
The B sample test will probably take place next week and won't happen in Germany. "We won't question the place. We'll follow the appropriate steps," Margossian said.
Margossian said he didn't know if the flu medicine that Carrera consumed before the fight could have affected the positive result. "Once we receive the final results, we'll forward them to the experts so they can analyze them. There has to be an answer," he said.
Margossian said Carrera "is mentally very well, surrounded by his family and his wife.
"Mariano is calm. We are hoping this can be overturned," he said.
Information from ESPNdeportes.com reporters Nicolas Baier and Andres Rodriguez Ferrari was used in this report.