Tong Wen blamed her positive clenbuterol tests on eating contaminated Chinese meat.

Olympic judo gold medallist Tong Wen won her appeal Wednesday against a two-year ban for a positive clenbuterol test that she blamed on eating contaminated Chinese meat.

The Court of Arbitration for Sport overturned the suspension imposed by the International Judo Federation, citing a "procedural failure" in the laboratory tests, and re-instated her as world champion.

"Tong's results at the 2009 World Championships are reinstated, she is to retain the gold medal won at those championships and she is to be reinstated to sports participation with immediate effect," the court said in a statement.

However, the verdict "should not be interpreted as an exoneration of her. In particular, the panel is not declaring that [Tong] did or did not, voluntarily or not, ingest clenbuterol," the ruling stated.

Tong tested positive for the muscle-building, fat-burning drug after winning the over 78-kilogram category at the August 2009 worlds in Rotterdam, Netherlands.

The judo federation later ordered tests on her backup "B" sample — which also had clenbuterol traces — without telling her or giving her the chance to attend the tests at the World Anti-Doping Agency lab in Cologne, Germany.

The CAS panel of three lawyers "recognized that the right of the athlete to be present applies whenever the 'B' sample is analysed, irrespective of who asks for it."

CAS said "no doping violation has been established" because the unofficial "B" test was not a valid confirmation of the original finding of clenbuterol.

Tong denied knowingly using the drug and blamed the failed test on eating contaminated Chinese meat. She initially asked for her backup sample to be tested but withdrew her request "following the advice of the Chinese Judo Association," the court said.

The judo federation went ahead and ordered the tests in November 2009, and suspended her five months later.

The Cologne lab handled Alberto Contador's urine samples from the 2010 Tour de France that tested positive for clenbuterol, which he claims came from eating Spanish beef. Contador was cleared by the Spanish cycling federation this month, and the International Cycling Union and WADA are weighing an appeal to CAS.

In documents submitted to CAS, Tong's lawyers also cited the case of German table tennis player Dimitrij Ovtcharov, who was exonerated after he, and four teammates, tested positive for clenbuterol from eating contaminated meat in China.

The judo federation said it would have argued that the drug would have left Tong's body in the week between leaving China and being tested in the Netherlands.

The federation's lawyers told CAS that clenbuterol is banned in the European Union so "the risk of finding clenbuterol-contaminated meat in Rotterdam is therefore very slim if not non-existent."

Tong's ban denied her the chance to seek a third straight title at the Asian Games in Guangzhou, China, last November.

The 28-year-old judoka's victory in Rotterdam was her fourth straight world title. She also won heavyweight gold at the 2008 Beijing Olympics.

The CAS decision makes Tong eligible to defend her title at next year's London Olympics. Under IOC rules, any athlete receiving a doping ban of six months or more is automatically banned from the next Olympics.

The judo federation's failure to observe rules meant the panel never considered both side's detailed arguments.

Tong employed lawyers who won back Olympic medals for two Belarussian hammer throwers by arguing that their samples which contained testosterone were mishandled by the Beijing laboratory.

Tong submitted a lie detector test in support of her claim of innocence, and her legal team prepared to argue that a lab machine was not calibrated properly to detect clenbuterol.