What are the main blood groups?
These are O, A, B and AB. Each group is also classified as either Rhesus D negative or Rhesus D positive.
How did I get my blood group?
Blood groups are inherited from your parents. The four blood groups, A, B, AB and O are controlled by the A, B and O genes.
The A and B genes are dominant and group O is dependent on the inheritance of an O gene from each parent.
The inheritance of the Rhesus D (Rh D)gene from either or both parents results in the Rh D positive blood group 'expression'.
The absence of the Rh D gene results in the expression of the Rh D negative blood group.
What are the most and least common blood groups?
44% of people in the UK have O group blood; 42% have A group blood.
The least common groups are B (10%) and AB (4%).
85% of the population are Rh D positive and 15% Rh D negative.
Is there one group that is extra special?
It doesn't matter how common or how rare your blood group is we still need to collect enough to have it there when patients need it.
But O Rh D negative blood, a less common blood group, can be given to anyone in an emergency and is also used for transfusion into babies.