Karl Landsteiner classified blood into A, B, AB, and O in 1909, establishing which blood group system?

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Multiple Choice

Karl Landsteiner classified blood into A, B, AB, and O in 1909, establishing which blood group system?

The main idea is how red blood cells carry specific surface markers that define an individual's blood type. Karl Landsteiner showed that people have antibodies in their plasma against the A or B antigens they do not possess, while their red cells carry A and/or B antigens. This leads to a simple classification: if red cells have only the A antigen, the person is type A; only the B antigen, type B; both A and B antigens, type AB; and neither antigen, type O. This is the ABO blood group system, the foundation for transfusion compatibility because mismatched combinations cause antibodies to bind and cause the cells to clump (agglutinate). It’s separate from the Rh system, which is defined by the presence or absence of the RhD antigen.

The main idea is how red blood cells carry specific surface markers that define an individual's blood type. Karl Landsteiner showed that people have antibodies in their plasma against the A or B antigens they do not possess, while their red cells carry A and/or B antigens. This leads to a simple classification: if red cells have only the A antigen, the person is type A; only the B antigen, type B; both A and B antigens, type AB; and neither antigen, type O. This is the ABO blood group system, the foundation for transfusion compatibility because mismatched combinations cause antibodies to bind and cause the cells to clump (agglutinate). It’s separate from the Rh system, which is defined by the presence or absence of the RhD antigen.

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