Objectives To identify ABO blood type from a child having discrepant results in forward and reverse ABO blood grouping by serological identification and genetic testing.Methods After routine serological detection with ABO blood group,the ABO gene and ABO blood group-A subgroup genotype were tested by PCR-SSP method.Results The Serological results showed that the specimen was positive type A (anti-A:1 +w),the reverse type is O type (Ac:2 +,Bc:4 +);PCRSSP A-subtype typing showed that the genotype of the child was Ax14/O2.Conclusion Difficult blood type identification sometimes need to combine serology and molecular biology methods to confirm.In this case,the phenotype of the child was Ax,and the genotype was Ax14/O2.