Blood Types

In some ways, every person's blood is the same. But, when analyzed under a microscope, distinct differences are visible. In the early 20th century, an Austrian scientist named Karl Landsteiner classified blood according to those differences. He was awarded the Nobel Prize for his achievements.

Landsteiner observed two distinct chemical molecules present on the surface of the red blood cells. He labeled one molecule "A" and the other molecule "B." If the red blood cell had only "A" molecules on it, that blood was called type A. If the red blood cell had only "B" molecules on it, that blood was called type B. If the red blood cell had a mixture of both molecules, that blood was called type AB. If the red blood cell had neither molecule, that blood was called type O.

If two different blood types are mixed together, the blood cells may begin to clump together in the blood vessels, causing a potentially fatal situation. Therefore, it is important that blood types be matched before blood transfusions take place. In an emergency, type O blood can be given because it is most likely to be accepted by all blood types. However, there is still a risk involved.

A person with type A blood can donate blood to a person with type A or type AB. A person with type B blood can donate blood to a person with type B or type AB. A person with type AB blood can donate blood to a person with type AB only. A person with type O blood can donate to anyone.

A person with type A blood can receive blood from a person with type A or type O. A person with type B blood can receive blood from a person with type B or type O. A person with type AB blood can receive blood from anyone. A person with type O blood can receive blood from a person with type O.

Because of these patterns, a person with type O blood is said to be a universal donor. A person with type AB blood is said to be a universal receiver. In general, however, it is still best to mix blood of matching types and Rh factors.

Almost 40% of the population has O+ blood

Patients with Type O blood must receive Type O blood

About half of all blood ordered by hospitals in our area is Type O

Type O blood is the universal blood type and is the only blood type that can be transfused to patients with other blood types

Only about 7% of all people have Type O negative blood

Type O negative blood is the preferred type for accident victims and babies needing exchange transfusions

There is always a need for Type O donors because their blood may be transfused to a person of any blood type in an emergency
If your blood type is . . .


Type >> You Can Give Blood To >> You Can Receive Blood From
A+ >> A+ AB+ A+ >> A- O+ O-
O+ >> O+ A+ B+ >> AB+ O+ O-
B+ >> B+ AB+ B+ >> B- O+ O-
AB+ >> AB+ >> Everyone
A- >> A+ >> A- AB+ AB- A- O-
O- >> Everyone >> O-
B- >> B+ B- AB+ >> AB- B- O-
AB- >> AB+ AB- AB- >> A- B- O-


Source: AABB.ORG