Blood Group: August (At)

Common:  ata is a high incidence antigen.

Causes HDN: Yes

Critical Titer: 1:16


For a long time, it has been thought that anti-Ata did not cause HDN. 3 of the anti-ata cases were unnamed, but identical. When the August blood group was formed they were named and identified as anti-Ata. [4] 

Anti-Ata can cause moderate HDN requiring phototherapy [1]. Anti-Ata can also cause hemolytic transfusion reactions [2, 3]. An experiment showed the survival for transfused mismatched cells is 95% at 1 hour, and 18% at 24 hours. [3]


1 -

2 -

3 -

4 -