【Objective】 To investigate the ABO genotyping result and analyze the genotype mismatch probabilities of the patients who have the potential need of blood transfusion. 【Methods】 Serology and polymerase chain reaction (PCR- SSP) were used to detect the ABO blood group phenotype and genotype of 502 hospitalized patients

respectively. The consistency of the two methods was checked

the frequencies of the ABO blood group genotypes in each phenotype were calculated

and the potential Genotype Mismatch Probability in case of undergoing blood transfusion without genotyping technique was analyzed. 【Results】 Serology and PCR-SSP had a 100% consistency in each ABO blood group phenotyping results. PCR-SSP found 5 common ABO alleles and 16 ABO genotypes. The heterozygote genotypes took up more than 50% in each phenotype. In case of undergoing blood transfusion without genotyping technique

the Genotype Mismatch Probabilities of each phenotype were: A: 65.98%

B: 57.39%

O: 56.95%

and AB: 22.55%. 【Conclusion】 PCR-SSP can identify 16 ABO blood group genotypes

and can identify ABO blood group genotype. In clinical blood matching test

potential risk exists if ABO blood group was detected only by serology

application of PCR-SSP ABO blood group genotyping in clinical practice would be useful in preventing unexplained blood transfusion reactions.