There are four main blood types: A, AB, B and O. AB positive is considered the universal recipient, and O negative is considered the universal donor.
Blood type frequency (U.S. population)
- O Positive blood—37%
- O Negative blood—7%
- A Positive blood—36%
- A Negative blood—6%
- B Positive blood—8%
- B Negative blood—2%
- AB Positive blood—3%
- AB Negative blood—1%
Blood type compatibility
Your ABO blood type is based on the presence or absence of the A and B antigens on your red blood cells. The A blood type has only the A antigen and the B blood type has only the B antigen. The AB blood type has both A and B antigens, and the O blood type has neither A nor B antigen.
By the time you are 6 months old, you naturally develop antibodies against the antigens your red blood cells lack. For instance, a person with A blood type will have anti-B antibodies, and a person with B blood type will have anti-A antibodies. If you have type A blood, you cannot receive B blood because your body's anti-B antibodies will fight the B blood's B antigens. It is crucial we have all blood types available to our patients.
| Type | O- | O+ | B- | B+ | A- | A+ | AB- | AB+ |
|---|---|---|---|---|---|---|---|---|
| O- | Yes | |||||||
| O+ | Yes | Yes | ||||||
| B- | Yes | Yes | ||||||
| B+ | Yes | Yes | Yes | Yes | ||||
| A- | Yes | Yes | ||||||
| A+ | Yes | Yes | Yes | Yes | ||||
| AB- | Yes | Yes | Yes | Yes | ||||
| AB+ | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |