The eastern China province of Jiangsu is conducting HIV testing of people who have sold blood since 1990, according to the provincial disease control center.
The province also ordered testing of the spouses and children of previous blood sellers who were found HIV positive.
A senior official at the center said on Monday that some people believed to have been infected with HIV when selling blood have yet to be traced.
Municipal governments will be responsible for testing registered local residents, while migrants will be tested at the disease control center of the county or city where they work.
By the end of June 2004, Nanjing, the provincial capital, had identified 165 HIV-positive people, 48 of whom had full-blown AIDS.
China passed a law in August 2004 prohibiting the purchase and sale of blood in a bid to stem its growing AIDS epidemic. It was the first time the disease has been targeted in a law.
The Ministry of Health has confirmed that 840,000 people in China are HIV-positive and 80,000 have full-blown AIDS. It estimates that the actual figure may be closer to 1 million.
But the World Health Organization fears the number of people currently infected may already be as high as 1.5 to 2.0 million. The WHO and UN Program on AIDS have warned that the number could climb as high as 10 to 15 million by 2010 if the epidemic goes unchecked.
As part of its effort to check the spread of the disease, China has made HIV/AIDS education compulsory from junior middle school to college nationwide.
China also launched pilot clinics last year to provide methadone maintenance therapy to intravenous drug users and programs to promote the use of condoms at hotels, colleges and nightclubs.
(Xinhua News Agency, China.org.cn March 21, 2005)