Blood Groups

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Four major blood groups: A, B, AB and O.

These four blood groups were originally identified by Karl Landsteiner in 1900. Your blood group is determined by the group of antigen in your red cells. Blood group A refers to the fact that you have A-antigens, blood group B has B-antigens. Blood group AB refers to the existence of both antigens, while type O has neither A nor B antigens.

Which types are most common and most rare?

Generally speaking, blood group O is the most common worldwide, but this varies according to ethnicity and geographical location. In Hong Kong, 40% of the population is type O, while types A and B are represented by about 26% of the population respectively. Interestingly, only 7% of Hong Kong’s population is type AB. Elsewhere in China, Beijing's population shows somewhat different results. Just 29% of the population there is type O, while types A and AB can be found in 27% and 13% of the population respectively. Overall in Beijing, type B is the most common blood type, found in 32% of the participants.

Which blood group is the “universal donor” and which is the “universal recipient”?

People having blood type O (commonly known as “universal donor”) can donate red blood cells to anybody, while those having blood type AB are “universal recipient”. As blood contains antigens and naturally occurring antibodies that have to be matched between donor and recipient, blood transfusion must be closely regulated. If a transfusion is given after an incompatible match, a condition of haemolysis can set in, resulting in the recipient’s blood losing its ability to carry nutrients and oxygen. In some cases, this may even be life-threatening.

For plasma donation, AB plasma is considered as “universal plasma” because there is no anti A or B antibodies. It is suitable for all recipients, regardless of blood group.

So are you my type?

The simplest and easiest way to know your blood type is to donate blood, because first-time blood donors receive a memorial badge indicating their blood type. Even more importantly, donating blood is a great way to help those in need. Why not do it today?