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
0 on the Assam register
well under 1 in 30 of people
0 on the Assam register
roughly 1 in 5 of people
0 on the Assam register
under 1 in 100 of people
0 on the Assam register
roughly 1 in 3 of people
0 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
Don't know your group?
Register anyway, choose "not sure". You'll know after your first donation, and camps test for free.
Register as a donorCompatibility 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.