Every blood type plays a vital role, but when it comes to saving lives in emergencies, one type stands out: O negative.
Commonly called the universal blood donor, this rare blood type is critically important to hospitals and trauma centers across the world. So why does O negative hold such a unique status? And what does it mean to have a "universal" blood type? Let's dive into those questions and more.
Why O Negative Is Considered the Universal Donor
A person's blood type is determined by the presence or absence of A and B antigens, which make up the ABO system, and the Rh (D) antigen, which determines whether their blood type is positive or negative.
These tiny molecules attach to the membranes of red blood cells and can trigger an adverse immune response if not recognized by the recipient's body. Because of these reactions, not all human blood can be safely transfused from one person to another.
...Unless, of course, a person's red blood cells don't have A, B or Rh antigens to cause a reaction in the first place! Those people have O negative blood and can donate red blood cells to anyone, regardless of blood type.
Is O Negative Blood Rare?
It sure is! Only about 1 in every 14 Americans have O negative blood. Its rarity, combined with its incredible versatility, means O negative blood is practically always needed to support local hospitals and patients.
O negative blood is often used for:
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Trauma and accident victims before blood typing is complete
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Premature or newborn babies, who are more sensitive to incompatible blood
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Cancer and surgery patients with rare or complex transfusion needs
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Patients with O negative blood
Who Can O Negative Receive Blood From?
While the rest of the world depends on O negative blood, universal blood donors are even more reliant on O negative donations. That's because people with O negative blood can only receive red blood cells from other O negative blood donors. Because they lack A, B and Rh antigens, their immune system will reject any other type.
This is why O negative donors are doubly important — they're universal donors, but when they themselves need a transfusion, they depend on others of the same universal donor blood type.
