O positive blood type
The most common blood type in the United States and worldwide, and the red cell type hospitals use most.
37.4%
about 1 in 3 people · #1 of 8
What O positive means
O positive red cells carry no A or B antigen but do carry the Rh D antigen. Because they lack A and B, they can be given to patients of groups A, B, AB and O, as long as the patient is Rh positive.
Many trauma services also use O positive red cells in emergencies for men and for women past childbearing age, saving scarcer O negative units for girls and women who could become pregnant.
The catch runs the other way: people with O positive blood carry both anti-A and anti-B antibodies, so they can only receive O red cells (O positive or O negative).
Plasma
O+ plasma can be given to O+, O-. A O+ patient can receive plasma from O+, O-, A+, A-, B+, B-, AB+, AB-. Plasma rules run opposite to red cells because plasma carries antibodies, not antigens.
Best way to donate
Whole blood or double red cells. O positive red cells can go to any Rh-positive patient, which covers roughly 85% of people, so it is the type blood banks run short of most often.
Genetics
ABO genotype OO; Rh genotype DD or Dd. Want to know what blood type your children could have? Use the blood type calculator.
Pregnancy
An O positive mother does not need anti-D (RhoGAM). Group O mothers are the usual setting for ABO haemolytic disease of the newborn, which is typically mild (jaundice) when the baby is A or B. Read the Rh factor guide.
O positive blood type FAQs
Who can O positive donate to?
O positive red cells can go to O+, A+, B+ and AB+ patients: every Rh-positive type.
Who can O positive receive from?
Only O positive and O negative red cells.
Is O positive a universal donor?
Not quite. O negative is the universal red cell donor. O positive is close, since it suits every Rh-positive patient, and is widely used in emergencies.