Blood Type: ABO Group and Rh Type

Blood type tests are one of the fundamental laboratory test types. A blood type test determines your blood's classification, based on the presence or absence of biological markers (antigens) on the surface of your red blood cells.

A blood type test can help determine paternity, because genetically certain parents can only give birth to children with blood types.

A blood type test also lets you know what kinds of blood your body can accept without causing a transfusion reaction. In an emergency, it may be important for medical personnel to know what your blood type is.

ABO Blood Typing

The ABO group is the most important in the transfusion of blood. After a blood type test, you may find that your blood is type A (A antigen present), B (B antigen present), AB (A and B antigen present), or O (neither A nor B antigen is present).

Type O is called the universal donor type because it can be safely given to anyone, regardless of the recipient's ABO blood type. Testing is still important for a type O person, though, because most type O people will suffer a transfusion reaction if they mistakenly receive blood with any antigens.

Rh Blood Typing

Rh blood typing is also important for transfusions. This blood type test determines whether the Rh-factor (D) is present (Rh-positive) or not present (Rh-negative) in your blood cells.

If blood type tests indicate that you are Rh-negative, you should always receive Rh-negative blood except if at all possible. Rh-positive patients can receive Rh-positive or Rh-negative blood.

What does the test include?

A blood type test will show your blood type and whether you are Rh-positive or Rh-negative.