15.3 ABO typing by molecular genetics - Molecular typing for red cell antigens

Whereas ABO typing by serological means is straightforward and extremely accurate, the genetics of ABO is complex, rendering ABO molecular typing by available methods unreliable. This is particularly so in people of African origin, where hybrid ABO alleles are present. As it is never acceptable to obtain a false ABO typing, prediction of ABO phenotype by molecular methods is not currently recommended.