Methods:ABO blood groups were identified by serological tests. B(A) alleles were determined by PCR-SSP and direct DNA sequencing at exons 6 and 7 of ABO gene.

• 方法:用血清学血型方法、PCR-SSP法和ABO基因第6及第7外显子直接测序的方法对B(A)血型和B(A)型等位基因进行检测。