Most blood group antigens among Chinese people are very homogeneous (e.g., D, 99.4%; K, 0%; Fya, 99.7%). The frequency of clinically significant alloantibodies detected by the authors' crossmatching was only 0.146 percent, suggesting that pretransfusion testing can be greatly simplified in Chinese populations.

The nonsecretor gene se is absent (or very rare) among Chinese in Taiwan and the previously reported Le(a+b–) phenotype in this population is in fact Le(a+b+) as proven by the presence of small amounts of Le^b antigen on red blood cells. Salivary ABH substances in this phenotype are usually (although not always) markedly reduced. The Chinese Le(a+b+) phenotype is postulated to be the result of a weak secretor gene Se^ω. Although the Le(a+b+) phenotype is very rare in Caucasians, it has a frequency of 25% in Chinese. All Le(a–b–) Chinese are ABH secretors and have varying amounts of Le^a and/or Le^b substances in saliva.

Sixteen cases of subgroup B3 and two cases of subgroup A1B3 were found among donated blood processed in Taipei Blood Donation Center. The frequencies of B3 and of A1B3 among group AB Chinese in Taiwan are about 1 in 900, and about 1 in 1800, respectively. The B3 red cells showed 1 to 2+ mixed field agglutination with anti-B, 2 to 3+ mixed field agglutination with anti-A, B, and 4+ agglutination with anti-H. Reverse grouping showed anti-A but no anti-B activity; saliva of secretors contained B and H substances. The significant low avidity of subgroup B3 and subgroup A1B3 red cells with both polyclonal and monoclonal antiserums, as compared with normal group B cells, coupled with the difference in the avidity of the reaction between monoclonal and polyclonal antisera with B3 and A1B3 red cells, suggest the possibility of a qualitative as well as a quantitative difference in the B antigen of B3 red cells.

In Taiwan, the prevalence of circulating anti-HCV is 2 percent among first-time voluntary Chinese blood donors, 10 percent among donors with elevated ALT levels (greater than 45 IU/L), and higher among older men. The carrier rate for HBsAg was 18.6 percent and the frequency of positive HBV marker(s) (HBsAg, anti-HBc, anti-HBs) was 86.4 percent among first-time donors. There is no significant correlation between HBV and HCV infections in Taiwan, because there is no significant difference in the frequency of anti-HCV among donors with or without HBV markers. The frequency of anti-HCV among qualified donors in Taiwan (ALT less than 45 IU/L, not tested for anti-HBc) is 1.8 percent, which is not significantly different from the frequency (1.6%) in donors with normal ALT and negative for HBV marker(s) (qualified donors by Western Standards). Therefore, ALT is the most important surrogate marker for HCV infection in Taiwan.

The para-Bombay phenotype occurs more frequently in Oriental than in white populations. This report describes the immunohematologic findings in 20 cases of the para-Bombay phenotype detected over a period of about 15 months in the Chinese population of Taiwan.

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The H-deficient phenotypes found in Chinese so far, have all been secretors of soluble blood group substances in saliva. The corresponding isoagglutinin activity (e.g. anti-B in OB(Hm) persons) has been found to be weak in all cases. To determine the clinical significance of these weak isoagglutinins 51Cr red cell survival tests were performed on three OB(Hm) individuals transfused with small volumes (4 ml) of groups B and O RBC. Rapid destruction of most of the RBC occurred whether or not the isoagglutinins of the OB(Hm) individuals were indirect antiglobulin test (IAGT) reactive. When a larger volume (54 ml packed RBC) of group B cells (weakly incompatible by IAGT) was transfused to another OB(Hm) individual with IAGT active anti-HI, the survival of the transfused RBC was 93% at 24 h, with 30% of the RBC remaining in the circulation at 28 d in contrast to 76% as would be expected if the survival was normal. Therefore when whole units of blood of normal ABO blood groups, compatible by IAGT, are transfused, the survival is expected to be almost normal. These weak isoagglutinins may not be very clinically significant and we suggest that when para-Bombay blood is not available, the compatibility testing for OA(Hm) persons should be performed with group A and group O packed RBC; OB(Hm) with group B and group O packed RBC: OAB(Hm) with groups A, B, AB and O packed RBC. For cross matching, the indirect antiglobulin test by a prewarmed technique should be used.