OBJECTIVETo investigate the molecular genetic basis of samples with ABO typing discrepancy and provide the guidline for identification and clinical transfusion for these samples.

METHODSSix cases with similar serological characteristics were collected. Serological method, PCR-SSP and direct sequencing of ABO gene were used to explore the underlying mechanism. Condition of clinical transfusion of patients was also reviewed.

RESULTSThree conditions were related with the ABO blood type discrepancy, which included weaken antigen (2 cases), weakened antibody (3 cases) and ABO subtype (1 case). The satisfactory effect of transfusion was achieved in all patients with the principle of the same blood type or the compatible crossmatch.

CONCLUSIONHeterogeneity has existed with the ABO group. Indivianals with same reaction pattern may result in different mechanisms.