The most common blood type worldwide is O-positive (O+), with about 42% of the global population having this blood type. In the United States, O-positive is also the most common, making up around 38% of the population. The O blood group lacks A and B antigens but can be Rh-positive or Rh-negative, with Rh- positive being more common. O-positive blood is particularly important for blood transfusions because it can be donated to any Rh-positive recipient of any blood group O, A, B, or AB. Other major common blood types include A-positive (about 31% worldwide) and B-positive (about 15% worldwide), whereas the rarest blood type globally is AB-negative (about 0.5%).
