Universal Blood Donor

The term universal blood donor is used to refer to a person who can donate blood to almost any individual in the world. In most of the cases, the blood group of the universal donor is O-. Approximately, only 7 percent of the US population and 5 percent of the world population have O negative blood type. Before we move on to understand what makes a person with O negative blood group a universal donor, let's have a brief look at some more aspects of blood type classification.

Antigens and Antibodies in the Blood

Each blood group differs from the other and these differences in various blood groups can be attributed to the presence or absence of antigens and antibodies in it. The antigens are located on the surface of the red blood cells, while the antibodies are found in the blood plasma. There are more than 20 genetically determined blood group systems known in the world today. But when it comes to blood transfusions, the ABO blood group system is undoubtedly the most popular blood group system in the world.

Blood Group Classification

According to the ABO blood group system, various blood types are divided into 4 groups - A, B, AB and O. At times, blood is also classified by its rhesus factor (Rh), a term used to refer to the presence or absence of a specific antigen in the blood. A universal blood donor, O- is also a component of this blood grouping system.

Blood Group	Antigen Type
A	Antigen A
B	Antigen B
AB	Both A and B
O	No Antigens

One should also take a note of the fact that not all blood groups are not compatible with each other, and any attempts to mix two incompatible blood groups can lead to severe effects on the individuals body. If an individual with A blood group is administered blood from a donor with B blood group, his body is bound to react with the antigens in the B type blood during transfusion. Blood type plays a crucial role in determining whether the said individual is a universal donor or receiver.

Universal Blood Donor

Initially, O- blood was considered to be the universal donor type, which meant that an individual with any blood type could accept blood from an individual with O- blood group without any harm of transfusion reaction. This was assumed on the basis that O negative blood group doesn't have any antigens in it and hence there would be no reactions. However, recent studies have highlighted the fact that even O- type blood can have some antibodies which may cause harmful reactions during blood transfusion. Although such cases are very rare, the possibility is always there. In emergency situations however, O negative blood can be administered to anyone, especially when there is a shortage of the required blood type or when it is a life-threatening situation for the patient. Because of this advantage, most of the blood banks make sure that they have this lifesaving O- blood in ample quantities.

Universal donors and recipients have a clear cut advantage over the other blood groups. Among all the blood types categorized in ABO blood group system, O- type blood is reactive to a very less extent, almost negligible, and that makes an individual with this blood type a universal blood donor. If you are one of these elite people with O negative blood group, you should get into touch with your nearest blood bank at the earliest.