Abstract: Objective  To identify the blood type B(A) which is rare to see, and to investigate the concerned clinical blood transfusion safety strategies.  Methods  Automatic blood analyzer was used to detect ABO blood group, and  the group typing   and reverse typing of a patient  were  found to be inconsistent. Then the blood type and gene sequencing of this patient and nine of the family members were identified by blood group serology and molecular biology to analyze the genetic characteristic of the blood group of this family and clinical transfusion research was conducted on them to ensure the safety of clinical blood transfusion. Results  Which wascontrasted with B101 gene sequence were all nt640A>G and B(A) 04/O01 by gene identification.There was no agglutination between serum B(A) and O, B, B(A) red blood cells. B(A) red blood cells do not agglutinate with type B(A) and AB serum.Conclusion  The group typing and reverse typing were identified as B(A) with blood group serology that could be further confirmed by molecular biological techniques; clinical blood transfusion should adopt autologous blood transfusion, sametype infusion and compatible blood transfusion.

Key words: ABO bloodgroup system, B(A) blood type, serology, Family investigation, ABO genotyping；DNA sequencing；safety transfu