In the UK, there are eight main blood types: A, B, AB and O, each with either Rh positive or negative. Blood type O is the most common, followed by A. The NHS Blood and Transplant organization encourages people to become blood donors to help those in need.
What is blood type?
Blood type is a vital component of immunology. Blood types are structures made up of proteins or sugars found on the surface of red blood cells. These structures differ among individuals and are classified according to Dr. Karl Landsteiner's ABO system, which was developed in 1900. Your blood type is determined by the sugar structure on the surface of your red blood cells. Blood type A is identified by one structure, while blood type B is identified by a different structure. If your red blood cells contain both sugar structures, you have blood type AB, and if they don't have any sugar structures, you have blood type O.
If you need a blood transfusion, another blood type is very important. Namely the Rhesus D blood group. This is also called the Rh factor. If the Rhesus D blood group is on the edge of your red blood cells, then you are Rh positive (RhD positive). If this blood group is absent from the edge of your red blood cells, you are Rh negative (RhD negative).
If your blood does not contain sugar structures but does contain the Rh factor, you are O positive (O+). If your blood contains the sugar structures of blood type A but not the Rh factor, you are A negative (A-).
The Rh factor is also determined by heredity. You receive a positive Rh factor (+) or a negative Rh factor (-) from both parents. If one parent gives a positive Rh factor (+) and the other gives a negative (-), the child automatically has a positive Rh factor (+).