In ABO typing, which subgroup is characterized by presence of anti-A1?

The subgroup characterized by the presence of anti-A1 is Ael. In ABO grouping, A subgroups are classified based on their ability to produce specific antibodies against various antigens.

A1 and A2 are the two primary subgroups of the A blood type. The A1 subgroup expresses A antigens that are complete and detectable on the red blood cells. In contrast, the A2 subgroup has weaker A antigen expression, which typically does not lead to the production of anti-A1.

However, the Ael subgroup is particularly unique as it is known to produce anti-A1 antibodies in the presence of the A1 antigen. This reaction typically occurs when the Ael individual's blood sample is mixed with A1 cells, leading to hemagglutination due to the interaction of anti-A1 with A1 antigens.

Understanding this distinction is crucial in blood banking and transfusion medicine, as detecting the presence of anti-A1 can help determine the precise ABO subgroup. This knowledge can significantly impact compatibility testing and transfusion practices.