Generally, people with O Negative blood type are known as universal blood donors, as they can donate blood to anybody irrespective of their blood group.
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 universal donors is O− (O Negative). Only about 7 percent of the US population and 5 percent of the world population is believed to have this blood type. Before we move on to see what makes a person with this 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 can be attributed to the presence or absence of antigens and antibodies in it. Antigens are located on the surface of the red blood cells, while antibodies are found in the blood plasma. There are more than 20 genetically determined blood group systems known in the world today. However, when it comes to blood transfusions, the ABO blood group system is undoubtedly the most popular 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 all blood groups are not compatible with each other, and any attempt 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 the universal donor type, which meant that an individual with any blood type could accept blood from an individual with this blood group without worrying about the threat of transfusion reaction. This was assumed on the basis that O− blood group doesn’t have any antigens in it and hence, it doesn’t react with other blood groups. 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 cannot be ruled out. In cases of emergency, however, O− 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. Because of this advantage, most of the blood banks make sure that they have reserves of this lifesaving blood type.
Universal donors and recipients have a clear advantage over the other blood groups. Among all the blood types categorized in ABO blood group system, O− type 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 those elite people with O− blood group, you should get in touch with your nearest blood bank at the earliest.
