Question

why is blood type AB- able to receive blood from all four blood types

Answer 1

The reason for using the same type of blood group or compatible type of blood during blood transfusion is the blood cells have antigens on the cell surface receptors and the plasma have antibodies that bind to those receptors and when the same type of antigens and the same type of antibodies are present in the blood, haemolysis takes place. Each blood type has the same type of antigen but the opposite type of antibodies. for example, if the blood group is A that means the blood has A type of antigen but B type of antibodies in the plasma, as a result, no haemolysis takes place.

The AB- blood type has both types of antigens in them but they don't have any antibodies in their plasma as a result even if they receive blood from any blood type they don't have antibodies to cause haemolysis.