About BLOOD

Blood Groups

Blood types

All human blood may look similar, but you can’t donate to anyone and you can’t receive blood from anyone. Different blood types need to be matched correctly.

Although all blood is made of the same basic elements, not all blood is alike. In fact, there are eight different common blood types, which are determined by the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body. Since some antigens can trigger a patient’s immune system to attack the transfused blood, safe blood transfusions depend on careful blood typing and cross-matching.

The ABO Blood Group System

  • ]Group A – has only the A antigen on red cells (and B antibody in the plasma)
  • ]Group B – has only the B antigen on red cells (and A antibody in the plasma)
  • ]Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
  • ]Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)
  • ]Bombay Group – In group ‘O’ individuals absence of ‘H’ antigen

There are very specific ways in which blood types must be matched for a safe transfusion

In addition to the A and B antigens, there is a third antigen called the Rh factor, which can be either present (+) or absent ( – ). In general, Rh negative blood is given to Rh-negative patients, and Rh positive blood or Rh negative blood may be given to Rh positive patients.
  • ]The universal red cell Donor has Type O negative blood type
  • ]The universal plasma Donor has Type AB blood type

Subtypes of Blood Group

ABO Rh Anti A Anti B Anti AB Anti A1 Anti H Anti D A Cell B Cell O Cell Du
A1 Pos Positive Negative Positive Positive Positive Negative Positive Negative
A1 Neg Positive Negative Positive Positive Negative Negative Positive Negative Negative