Are You My Type? A Note on Blood Typing

If you’ve ever needed to receive blood, you know that getting the right type is very important. You may also know that there are 8 different blood types (O+, O-, A+, A-, B+, B-, AB+ and AB-), but what is it exactly that makes blood one type or another?

While all blood contains red blood cells, white blood cells, plasma and platelets, the type of antigen the blood has determines its type. Antigens are sugars or proteins that make the body’s immune system act a certain way. Antigens found in the body’s own cells are called “self-antigens,” and the immune system does not usually attack them. If an outside antigen gets into the body, however, white blood cells will attempt to destroy it.

There are two main blood groups: ABO and Rh. In ABO blood groups, the antigen is a sugar that dictates which letter your blood type falls into (A, B, AB, or O).

  • AB blood types have both A and B antigens on red cells.
  • A blood types have only the A antigen on the red cells.
  • B blood types have only the B antigen on the red cells.
  • O blood types have neither A or B antigens on the red cells.

The second group – the Rh group – is determined by either the presence or absence of a protein antigen called the D antigen. Whether or not you have this antigen determines if you have a positive or negative blood type.

What happens, though, if you receive the wrong blood type?

While the chances of that happening in a hospital are very rare, getting the wrong blood type transfused can be fatal. The immune system of the person receiving the transfusion will attack the donor’s blood, frequently causing the body to go into shock. Symptoms of a transfusion reaction are flu-like: chills, fever, shaking, headache, chest or back pain, and body aches are the most common. Usually, the symptoms show up during the transfusion, but sometimes it can take several days.

By donating blood, you can help ensure there is enough blood available at hospitals for those who need it. It’s also a great way to find out your own blood type! So stop by a blood drive or blood center and help your local hospitals. Who knows? You may end up saving the life of someone you know.