Blood Types

There are two types systems the blood technicians use to categorize blood. The first system is the ABO System and the second is Rh factor system.  The ABO system has 4 different groups and they consist of group A, group B, group AB, and group O. The Rh factor system only has 2 groups so you are either (+) positive or (-) negative. Technicians use both of these systems together to identify a person's blood type. Combine they make up 8 blood types a person could be classified under.

                   A+         B+         AB+         O+

             A-          B-          AB-           O- 

  In the chart below you will see the many ways blood types can be compatible with other blood types. (O-) blood can be given to any blood type so they are considered a "Universal Donor." A person with (AB+) blood can receive all types of blood and is considered a "Universal Receiver." A person with (A) blood type can only be given (A) or (O) type blood. This is the same for (B) type blood. They can only be given (B) or (O) type blood. 

The immune system is the body's protection against invaders. It can identify antigens as self or nonself. To get a blood transfusion safely, a person's immune system must recognize the donor cells as a match to his or her own cells. If a match isn't recognized, the cells are rejected.