Blood Group
Blood is the basic and important element of our body. Blood is the mixture of white blood cells, red blood cells, platelets and plasma which is the liquid component of blood. Our body contains 5 liters of blood. Blood circulates throughout the body and provides nutrients and oxygen to various body parts and tissues. It also helps to eliminate carbon dioxide and other waste products from the body.
ABO System
The blood groups are classified into 4 different types, which is determined by the presence or absence of antigens A or B. Antigens are the substances that trigger an immune response if they are foreign to the body. The most commonly used blood group system is ABO system or Landsteiner system.
Blood Group A- Only antigen A is present on the red cells and antibody B in the plasma
Blood Group B - Only antigen B is present on the red cells and antibody A in the plasma
Blood Group AB - Both antigen A and B is present on red cells and no antibody present
Blood Group O - Neither antigen A or B is present on the red cells both antibody A and B
are present in the plasma.
In addition to these four types ,blood groups are further classified based on the presence or absence of protein Rhesus which is called as Rh factor (Rh negative blood and Rh positive blood).
Rh negative blood is given to negative blood group patients and Rh positive blood is given to Rh positive patients.
Blood group O Rh- is called as Universal Donor as blood group O do not have antigen A or B in the blood and can be transfused to any other blood group without any blood clumping. Hence blood group O patients can donate blood to any blood group (A,B, AB or O)
Blood group AB Rh+ is called as Universal Recipient as AB do not have antibodies in the plasma and has both the antigen A and B in red cells. Hence blood group AB can receive blood from person with blood group A, B, O or AB.
What happens when blood don't match?
For blood transfusion, it is necessary to match ABO and Rh blood group between donor and patient's blood. If they are not matched then the RBC's will agglutinate or clump. The clumped RBC's can block the blood vessels and stop the circulation which ultimately leads to the organ failure and the patient may die. For Ex- If blood group A person receives blood group B blood then RBC's combine together, form the clog and block the blood flowing through the blood vessels. Hence there will be no circulation and the patient dies.
In the same way Rh- blood cannot be given to Rh+ patient as the blood will cause clumping and leads fatal to the patient.
Table which represents the suitability of blood transfusion to the different blood groups.
|
Recipient |
DONOR |
||||||||
|
A+ |
A- |
B+ |
B- |
O+ |
O- |
AB+ |
AB- |
||
|
A+ |
Yes |
No |
No |
No |
Yes |
Yes |
No |
No |
|
|
A- |
No |
Yes |
No |
No |
No |
Yes |
No |
No |
|
|
B+ |
No |
No |
Yes |
No |
Yes |
Yes |
No |
No |
|
|
B- |
No |
No |
No |
Yes |
No |
Yes |
No |
No |
|
|
O+ |
No |
No |
No |
No |
Yes |
Yes |
No |
No |
|
|
O- |
No |
No |
No |
No |
Yes |
Yes |
No |
No |
|
|
AB+ |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
|
|
AB- |
No |
Yes |
No |
Yes |
No |
Yes |
NO |
Yes |
|
The above table denotes the compatibility and non-compatibility of blood groups. Ex. A Rh+ blood can be given to A Rh+ patient but not the same incase of A Rh-.