Why is blood typing important in blood transfusions?
1 Answer
Because if the wrong type of blood is administered, the body's immune system can attack it and this can have potentially harmful effects.
Explanation:
The various blood types and subtypes that exist (A+, A-, B+, B-, AB+, AB-, O+, and O-) are classified according to the presence or absence of certain surface antigens that, for convenience, are labelled A, B, and D (for Rh).
The presence of A surface antigen makes the blood group A.
The presence of B surface antigen makes the blood group B.
The presence of both A and B surface antigens makes the blood group AB.
The absence of both A and B surface antigens makes the blood group O.
The presence of D surface antigen makes the blood group Rh+.
The absence of D surface antigen makes the blood group Rh-.
People of group AB+ (universal recipients) can receive blood from any other blood group since their immune system will not mount an immunological defence against any of the surface antigens.
Similarly, people of group O- (universal donors) can donate blood to any other blood group since the absence of these three surface antigens prevents the immune system of the recipient from mounting an immunological defence.
But, for example, if blood group A is transfused into a person of blood group B, the recipient's immune system will attack the donated blood as foreign. While an initial transfusion might not cause much harm beyond destruction of the received blood and pyrexia, an enhanced immunological response is possible with a larger transfusion or multiple transfusions.
This response which involves an attack on the donated blood can cause shock, kidney failure, collapse of the circulatory system, and even death.
