Blood Typing: Mixing Blood/Transfusions & +/- Blood

Transfusions are intended to save a lives. A transfusion is taking blood from one blood type and giving it to someone with the same blood type to help them with things like massive blood loss due to trauma. Although various diseases can be passed from one to another through transfusions like HIV, Hepatitis B and C, Malaria etc.

Have you ever wondered why people bother with blood typing? Or why people who donate blood have to have their type verified first?

Is because blood typing is very important when doctors make transfusions or mix different kinds of bloods. In fact, there is a whole field devoted to taking blood samples and studying them: its called Phlebotomy.

Transfusions are intended to save a lives. A transfusion is taking blood from one blood type and giving it to someone with the same blood type to help them with things like massive blood loss due to trauma. Although various diseases can be passed from one to another through transfusions like HIV, Hepatitis B and C, Malaria etc.

There are several different kinds of blood (A, B, AB, O, positive or negative, etc). They are usually based on two systems, the AbO system (A, B, AB, and O) and the Rh system (positive or negative). The Rh system classifies blood as positive or negative depending on whether or not it contains the RhD antigen. If it does, it is positive, and if it does not, it is negative and likely to make anti-RhD if exposed to the RhD antigen through transfusion. Therefore, when you receive a blood transfusion, the type of blood you receive should match your own blood type. If it doesn't, your immune system may form antibodies and begin attacking the donor blood because it does not recognize it. However, a person with blood type AB can receive from either A, B, or O individuals but can only donate to another person with AB type blood. Someone with blood type A can donate to either an A or AB, but can receive from O (because it does not have any antibodies) and other people with type A blood. Type B blood can be donated to either AB or B and can receive from either B or O. Type O blood can donate to any of the other types (A, B, AB) but can only receive from O.



The RhD is also a very important factor. If the RhD is not the same then the consequences would be the same as mixing two different types of blood. RhD refers to the absence (-) and the presence (+) of the Rhesus, a type of antibody. This was discovered in an experiment in 1937 where Karal Landstiner and Alexander S. Wiener discovered that rabbits, when immunized with rhesus monkey cells, created agglutinates, an antibody.