There is increasing agreement that Australia antigen (Au)-positive subjects should not be accepted as blood donors. This practice is being adopted in Western countries where the frequency of Au is approximately 0.1%. The frequency of Au is much higher1 in tropical countries.
The serum samples of 98.4% (2,563) of all donors in January 1971 were screened by electro-osmodiffusion (EOD)2 in order to investigate the frequency of Au in blood donors in Singapore (Table 1). The Au carrier rate was relatively high. An ethnic difference in carrier rate in that Chinese had a higher frequency than Malays, Indians, and others was observed.
All except nine serum samples were reexamined for Au by immune adherence haemagglutination (IAHA) (Table 2). The IAHA is approximately 1,000 times more sensitive than EOD.3 Twice the number of Au carriers were detected by the more sensitive technique. The ethnic difference suggested by the EOD
Malcolm J. Simons, Eu Hian Yap, Yong Wan Ong, Kazuo Okochi, M. Mayumi, Kusuya Nishioka. Frequency of Australia Antigen in Blood Donors in Singapore. Am J Dis Child. 1972;123(4):405–406. doi:10.1001/archpedi.1972.02110100137051