Health Certification

Under the requirements for the Foreign Experts Certificate issued by the State Bureau of Foreign Experts of the PRC, it says applicants must submit:

"The copy of the health certificate that is still effective within one year and given by foreign medical organizations authorized by Chinese embassies and consulates in foreign countries or by quarantine office authorized by Chinese government."

Where does one obtain such a certificate, and who are the medical organizations authorized by Chinese embassies and consulates? In the past, I've always gotten a health exam after arriving in China. I've tried calling every embassy possible (Los Angeles, San Francisco, New York, Chicago, Houston, Beijing, the Bureau itself), but no one's ever available to answer this question!