Olympic champ insists documents support his claim amid doping case

China's Olympic champion swimmer Sun Yang has accused a nurse involved in his doping case of not possessing the correct credentials and therefore collecting his blood sample illegally.

"She violated provincial regulations for China's nurses. Worse, she did not have a valid nursing qualification certificate, or a nursing professional certificate, and only showed me an expired certificate," Sun wrote on Weibo.

Sun also criticized what he described as the unfair treatment of Chinese athletes at a Court of Arbitration for Sport (CAS) hearing in Montreux, Switzerland, on Nov 15.

The case centers on Sun's alleged non-cooperation with three testers on Sept 4.

The World Anti-Doping Agency (WADA) appealed to CAS against an initial ruling by swimming's world governing body, FINA, not to sanction Sun for alleged anti-doping violations.

The three-time Olympic champion said that on the night in question, three anti-doping officers from international testing company IDTM refused to show him their authorized certification, documents and valid accreditation.

In a picture posted on Weibo, Sun showed two nursing certificates in blue covers: a qualification certificate and a professional certificate.

The 28-year-old freestyle specialist wrote on Weibo: "According to regulations on China's nurses, those who practice across geographical areas must go through the relevant registration and filing procedures, otherwise they may not practice in areas other than where they are registered.

"If such rules are violated, the relevant medical and health institutions shall make a decision on handling such a case according to the law.

"The World Anti-Doping Regulations and ISTI(International Standard for Testing and Investigations) standards clearly state that the blood inspectors should first comply with the mandatory legal provisions of the country in which the blood collection is conducted.

"The blood inspector had her nurse practice registration for a hospital in Shanghai, so how could she illegally collect my blood in Hangzhou?

"The most critical part was that she only showed me an expired nursing qualification certificate, rather than a valid one, and she also had no nursing professional certificate. I am very curious to know how the relevant medical and health institutions in Shanghai will deal with the illegal acts of the blood inspector."

One of the three IDTM testers has told Xinhua he was not a trained Doping Control Assistant (DCA) but a construction worker.

The man, who insisted on anonymity, said "he had never been trained as a doping control officer", adding that he was providing temporary help for IDTM at the request of a former middle-school classmate, who works for the company.

"I sent my testimony in a written letter to CAS and WADA and was ready to testify via a video conference call before the public hearing, but no one contacted me," said the "temporary" DCA.