The eight groups
Know your group. Know your power.
Every group helps someone, but each helps differently. Common groups are needed constantly; rare negative groups are what banks run out of first in an emergency.
roughly 1 in 3 of people
4 on the Assam register
well under 1 in 30 of people
0 on the Assam register
roughly 1 in 5 of people
3 on the Assam register
under 1 in 100 of people
0 on the Assam register
roughly 1 in 3 of people
4 on the Assam register
roughly 1 in 90 of people
0 on the Assam register
roughly 1 in 13 of people
0 on the Assam register
roughly 1 in 250 of people
0 on the Assam register
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Two facts decide most transfusions: your group, and whether you are Rh positive or negative. O negative works for almost everyone in an emergency, which is why it disappears first when stock runs low, while AB positive patients can receive from all groups. To go deeper: which groups are rare in India, who can give to whom, exactly, how compatibility actually works, and what Rh means for you. Pregnant or planning? Read blood groups in pregnancy next.
Compatibility questions
Which blood group is the universal donor?
O negative, its red cells can be given to patients of every group, which is why O− stock runs out first in emergencies. O positive can also help most patients (everyone positive), making both O groups constantly needed.
Which blood group is the universal recipient?
AB positive, patients can receive red cells from every group. The mirror image: AB+ donors matter most for AB+ patients, and AB plasma can help everyone.
What are the rarest blood groups in India?
AB negative (roughly 1 in 250), B negative and A negative. All negative groups run short first because they can only receive from other negatives.
Does blood group compatibility matter for plasma too?
Yes, and the rules are partly inverted: AB plasma is universal while O plasma only suits O patients. Red-cell charts do not cover plasma, the blood centre decides every match.