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The ABOs of blood types
Originally Published: March 21, 1997 ~ Last Updated / Reviewed on: January 04, 2008
 

Dear Alice,

Can an A+ person receive any blood type other than their own? If so which ones? Which blood type is the universal receiver and which is the universal donor?

 

Dear Reader,

A person with an A+ blood type can receive blood types A and O (A+, A-, O+, and O-).

And here's why.... Blood types are determined by ABO blood grouping, which is based on two inherited antigens called A and B. An antigen is anything capable of inducing an immune reaction, and, in this case, A and B are proteins which are found in red blood cell membranes. The presence, or absence, of antigens and antibodies in your plasma will determine which blood type you can receive. See the table below for information about the antigens and antibodies specific to your blood type:

Blood Type
A
B
AB
O		 Antigens
A
B
A and B
None		 Antibodies in Plasma
Anti-B
Anti-A
None
Both Anti-A and Anti-B

So, what does this table mean? Your blood already contains antibodies against any antigens you do not manufacture yourself. For example, if you are type A, you cannot accept B and AB blood types because you will have a transfusion reaction, which is a special kind of tissue rejection. Basically, your anti-B serum antibodies will react with the B antigens of the donor and result in agglutinated blood (aggregation of red blood cells into clumps) that destroys the donor's cells. This reaction, if severe enough, could cause complications and possibly death. If you are type AB, since you have no antibodies against either A or B antigens in your blood, you will not experience an immune response to any blood type you receive. On the other hand, if you are type O, you can receive only type O blood because you have antibodies to both A and B antigens in your blood, which will cause an immune response to all other blood types received.

Below is another table that will better explain compatible blood types:

Recipient
A
B
AB
O		 Donor
A, O
B, O
A, B, AB, O
O

As you can see, type AB is considered the universal recipient blood type because, theoretically, type AB individuals can receive all blood types (and is the only blood type that can accept type AB blood). Type O blood is considered the universal donor blood type because, theoretically, type O blood is accepted by all blood types. An emphasis is placed on theoretically because A and B are not the only antigens present on the surface of your blood cells. There's another important antigen carried on a separate gene called the Rh antigen. If you have the A antigen and the Rh antigen, your blood type is A+. If you don't have the Rh antigen, you're A-. O- is the universal donor blood type because it has no A, B, or Rh antigens, and, therefore, won't cause a transfusion reaction in anyone.

If you don't know your blood type, find out what it is because as you now know, it's a good thing to know in case you need a blood transfusion. At the same time, even if you already know your blood type, you may expect to be retested in order to prevent a reaction caused by minor antigens. As far as blood transfusions go, you will most likely receive a portion of blood, such as "packed red cells" or serum, rather than whole blood, which is rarely transfused these days.

Alice

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