Rare Blood Types

The first blood transfusion on humans was performed around 1600 with animal blood and the results were disastrous. It was in 1800s that James Blundell proposed the concept of using human blood transfusion for human beings. However, it was only in early 1900s that the four types of blood group were identified by Karl Landsteiner. This lead to successful blood transfusions in humans and better results were produced when the type of blood was the same in the donor and receiver.

Blood Types

A blood type, also known as the blood group is the classification of blood bases based on the presence or absence of antigens that we inherit from our parents and is present on the surface of the red blood cells. These antigens can be proteins, carbohydrates, glycoproteins or glycolipids and depends mainly on the blood group.

To identify the blood type, the presence or absence of these immunogenic blood group antigens, classified as antigen A, antigen B along with the antigen RhD is identified. The type is stated as a combination of either A or B along with the presence or absence of the RhD antigen, for example, A positive, B negative, etcetera. The blood type AB indicates the presence of both A and B antigens while the blood type O indicates the absence of both types of antigens.

Red Blood Cell Compatibility

• AB Group: Individuals with the blood group AB contain both antigen A and antigen B. Hence, they can receive blood from individuals of all blood groups but can donate blood only to people who have the AB blood group.
• A Group: Individuals with the blood group contain antigen A. Hence, they can receive blood from individuals who have the blood group A or O and can donate blood to people who have A or AB blood group.
• B Group: Individuals with the blood group contain antigen B. Hence, they can receive blood from individuals who have the blood group B or O and can donate blood to people who have B or AB blood group.
• O Group: Individuals with the blood group do not contain antigen A or antigen B. Hence, they can receive blood from individuals who have the blood group O and can donate blood to people who have A, B or AB blood group.

Apart from these, people who have the RhD antigen present in their blood can receive blood from people whose blood may or may not contain the antigen while people who do not have the RhD antigen present in their blood cannot receive blood which contains the antigen RhD. However, this particular antigen does not come into the picture when plasma is to be donated or received. The listing mentioned above holds good.

From the list above it is easy to understand as to why people with blood group O (especially O negative) are referred to as ‘universal donors’ and people with blood group AB (especially AB positive) are referred to as ‘universal recipients’.

Rare Blood Types

I was very surprised to read that the concentration of a blood group varies in ethnic groups and geographically too. In the United States of America, the rarest blood type is AB Negative. It has been estimated that only about 1 in about 170 people have this blood type. However, as people with this blood group can be transfused with all other blood groups, even in cases of low resources, there is not too much of an issue. Next in line is the B Negative blood type. About 1 in every 70 people has this blood type.

The most common blood group is the O Positive blood group. In a way this is our good fortune as people with this blood type can donate blood to all people who have any blood type with the RhD antigen present.

With the advance in technologies over the years, the human race has been able to understand as to which blood type of blood is best suitable for transfusion to a particular individual. It is up to us to use this information diligently. Be well advised so that when there is an emergency, you can take a well informed decision which will not lead to any unnecessary complications.