When an individual is in need of a blood transfusion, it is important that the blood given is compatible with the recipient’s blood type. If the donated blood is incompatible, the recipient’s immune system will reject the donated blood as foreign, causing the RBC (Red Blood Cells) to clump together (Agglutinate) which marks them for destruction by macrophages. The danger is that agglutinated blood will clog small vessels which starves the associated tissue of resources. This is a potentially lethal situation.
Determining whether blood types are compatible depends on the type of molecules on the surface of the donated blood (called antigens) and whether the recipient has antibodies that will bind to the antigens on the donated blood. Antibodies are immune proteins within the recipient’s blood plasma that bind to foreign antigens, tagging them for destruction. An individual’s blood type is a label that indicates the type of antigens present on the surface of his/her RBC.
In the human population, there are certain antigens that are common. In the ABO system, individuals can either have A antigens (Type A), B antigens (Type B), both A and B antigens (Type AB), or neither A nor B antigens (Type O). In the Rh system, individual can either have the D antigen (Rh+) or lack the D antigen (Rh-). These two systems are usually combined so that there are 8 blood types in the human population, A+, A-, B+, B-, AB+, AB-, O+, and O-. These 8 blood types can be depicted as follows…
Type A+ Type A- Type B+ Type B-
Type AB+ Type AB- Type O+ Type O-
Individuals also have antibodies associated with the ABO or Rh antigens that protect them from foreign blood. For example, anti-A antibodies will attack A antigens on a RBC. Individuals will have antibodies that will NOT attack their own blood. The following table lists the 8 blood types and the corresponding antibodies present in the individual’s blood plasma.
Antigens Antibodies Antigens AntibodiesBlood Type on RBC in plasma Blood Type on RBC in plasma
Type A+ A & D Anti-B Type AB+ A, B, & D None
Type A- A Anti-B & Anti-Rh Type AB- A & B Anti-Rh
Type B+ B & D Anti-A Type O+ D Anti-A & Anti-B
Type B- B Anti-A & Anti-Rh Type O- None Anti-A, Anti-B, & Anti-Rh
Key to Compatibilities: Determine the kind of antibodies present in the recipient’s blood plasma. RBC from compatible donors will not have the surface antigens that the recipient’s antibodies would attack.
Example #1. The recipient is Type A+, he/she has Anti-B antibodies. Compatible donors cannot have the B antigen. So, of the 8 possible blood types, A+, A-, O+, and O- are all compatible because they lack the B antigen. B+, B-, AB+, and AB- are all incompatible because they have the B antigen.
Example #2. The recipient is Type O+, he/she has Anti-A and Anti-B antibodies. So, of the 8 possible blood types, O+ and O- are compatible because they lack the A and B antigens. A+, A-, B+, B-, AB+, and AB- are all incompatible because they have either the A antigen, the B antigen, or both.
Answer the questions below about blood types. Note that similar questions will also be asked on the lecture exam.
1 point per blank.
The recipient of a blood transfusion is Type A-. What kind of antigen(s) are on the surface of his/her RBC? __
The recipient of a blood transfusion is Type B+. What kind of antigen(s) are on the surface of his/her RBC? __
The recipient of a blood transfusion is Type AB-. What kind of antibodies are present in his/her blood plasma? _______________
The recipient of a blood transfusion is Type A+. What kind of antibodies are present in his/her blood plasma? _______________
2 points per blank
The recipient of a blood transfusion is Type A-. Of the 8 blood types in the human population, list the blood types of all compatible donors. _____________
The recipient of a blood transfusion is Type O-. Of the 8 blood types in the human population, list the blood types of all compatible donors. _____________
The recipient of a blood transfusion is Type AB-. Of the 8 blood types in the human population, list the blood types of all compatible donors. _____________
The recipient of a blood transfusion is Type B+. Of the 8 blood types in the human population, list the blood types of all compatible donors. _____________
Of the 8 blood types in the human population, which blood type is the universal recipient, (i.e. an individual with this blood type can receive any of the 8 blood types)? __
Of the 8 blood types in the human population, which blood type is the universal donor (i.e. this blood can be donated to anyone, regardless of his/her blood type)? __
