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 How does the unit of blood get from the donor to the recipient?
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Separation of various Blood Components
Following whole blood donation, the various blood components are separated immediately by a centrifugation process into the different components such as red cells, plasma, and platelets. These various blood components can then be transfused to the recipients according to their needs. Hence, a pint of blood from one donor can save the lives of many people. |
Infection Screening
Before any blood components can be transfused, they are quarantined for 24 hours. A series of blood tests are carried out to exclude certain infectious diseases which can be transmitted through blood transfusions. These tests include HIV, Hepatitis B, Hepatitis C and Syphilis. Blood can only be transfused when all 4 infectious agents are excluded. |
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Blood Typing and Cross Matching
The blood type of a person is established through specific proteins called antigens found on the surface of red cells as well as antibodies in the plasma. There are 4 basic ABO blood types. They are Type A, B, AB and O. Blood Group "O" persons are "universal blood donors" and Blood Group "AB" are " universal recipients".
Each unit of donated blood is ABO and Rhesus D typed. When a patient requires blood transfusion, the ABO and Rhesus D blood group is determined. An antibody screening test is carried out on the patient to exclude any unknown red cell antibodies. Incompatible blood can cause severe symptoms to the patient. Red cell antibodies found in the patient can attach to the antigens on the donor's red cells and can cause red cell destruction. Blood is must be cross-matched between the patient and the donor to exclude any potential reactions before it is deemed compatible for transfusion.
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| Blood Group |
Antigens on Cells |
Antibodies in Plasma |
Population Distribution |
| A |
A |
Anti-B |
25% |
| B |
B |
Anti-B |
25% |
| AB |
A,B |
None |
5% |
| O |
None |
Anti A, Anti B |
45% |
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