Abstract

The propositus was 25 year old primigravida who was admitted to this hospital in March, 1982 for full term delivery. In routine blood typing, her cells were herr weakly agglutinated by anti-B serum, whereas revealed strong reaction by anti-A, anti-AB, and anti-H serum. Her serum didn't react with A,B, and 0 cells. Under the impression of A weak B, adsorption and elution studies of the cells, and neutralization studs of saliva and serum were performed. As a result, her blood type was proven to be A weak B and classified into second category of Race and Sanger, that is "no anti-B in serum(or very weak cold anti-B) : B in saliva" Her father and an elder roister were proven to have weak B in the family studs. (weak B in the father and A weak B in an elder sister).