AB negative is the rarest blood type in the United States. Only about 0.6% of the U.S. population has it, which works out to roughly 1 in every 167 people. That makes it significantly less common than even other “rare” types like B negative (about 2%) or O negative (about 7%).
How AB Negative Compares to Other Blood Types
Blood type frequency varies widely. O positive is the most common type in the U.S., carried by about 37% of the population. A positive follows at around 36%. From there the numbers drop quickly: B positive sits near 8%, and O negative around 7%. AB positive, which shares the same ABO grouping as AB negative but carries the Rh protein, is found in about 3% of people. AB negative, lacking both common genetic advantages that drive higher frequency, lands at the bottom.
Two things have to happen genetically for someone to end up with AB negative blood. First, you need one A allele from one parent and one B allele from the other, giving you the AB combination. Neither allele dominates the other, so both A and B markers appear on your red blood cells. Second, you need two copies of the recessive gene that results in Rh-negative status, one from each parent. Both of these inheritance patterns are relatively uncommon on their own. Together, they’re very uncommon.
Rarity Varies by Ethnicity and Region
AB negative blood is rare everywhere, but how rare depends on your ancestry. Rh-negative blood of any type is far more common in people of European descent. About 15 to 17% of people in Britain and the U.S. are Rh-negative overall. In contrast, Rh-negative prevalence drops to 1 to 7% in Ethiopian populations, around 6% in Nigeria, and below 1% in China, Indonesia, and Japan. In a large study from Ghana’s Volta region, AB negative was the least common blood type across every ethnic group examined, found in fewer than 1% of people in each group and as low as 0.1% overall.
This means if you’re of East Asian or African descent, AB negative is exceptionally rare in your community. If you’re of European descent, it’s still the rarest type, just slightly less so.
Why AB Negative Blood Matters for Transfusions
If you have AB negative blood, you can receive red blood cells from any negative blood type: O negative, A negative, B negative, and AB negative. You cannot, however, safely receive Rh-positive blood without risking an immune reaction. That still gives you more donor options than many other blood types, since any Rh-negative donor is compatible.
Where AB negative people become especially valuable is as plasma donors. Plasma compatibility works in the opposite direction from red blood cell compatibility. AB plasma, whether positive or negative, contains neither anti-A nor anti-B antibodies, which means it can be given to patients of any blood type. This makes AB negative individuals universal plasma donors. Blood banks actively seek AB negative donors for this reason, even though fewer than 1% of the population qualifies.
Blood Supply Challenges
The rarity of AB negative blood creates a persistent supply problem. Blood banks can’t stockpile it the way they can O positive or A positive, because so few donors walk through the door with that type. When an AB negative patient needs a transfusion, hospitals sometimes have to pull from regional reserves or request emergency shipments.
There’s an additional testing challenge. Weak variants of the A or B antigen can occasionally cause AB blood to be mistyped during screening. When these subtypes go undetected, a donor’s blood might be labeled as a single type (A or B) rather than AB. In rare cases, this mislabeling can lead to reduced cell survival or delayed reactions after transfusion. Advanced molecular testing can catch these discrepancies, but not all blood centers, particularly in lower-resource settings, have access to it.
Pregnancy and Rh-Negative Status
Being AB negative during pregnancy carries the same Rh-related considerations as any other Rh-negative blood type. The concern isn’t the AB part. It’s the negative. If you’re Rh-negative and your baby is Rh-positive (which happens when the father carries at least one Rh-positive gene), your immune system can develop antibodies against the baby’s blood cells. This is called Rh sensitization, and while it rarely causes problems in a first pregnancy, it can lead to serious complications in future pregnancies.
The standard prevention is an injection of anti-D immunoglobulin, typically given around 28 weeks of pregnancy. If the baby turns out to be Rh-positive at birth, a second dose is given within 24 hours of delivery. This treatment is highly effective at preventing sensitization. A meta-analysis of available evidence strongly supports its use in all unsensitized Rh-negative pregnant women.
The blood supply issue also comes into play during delivery. Because Rh-negative blood is harder to source quickly, some medical teams recommend that Rh-negative pregnant women bank their own blood before their due date. Autologous blood storage, collecting up to 400 ml of your own blood in advance, eliminates compatibility concerns entirely and has been shown to be safe for both mother and baby when done under medical supervision. This approach is particularly useful for AB negative mothers, whose matching donor pool is the smallest of any blood type.
What to Know if You’re AB Negative
If you’ve been told you’re AB negative, the most practical thing you can do is donate blood or plasma regularly. Your plasma is universally compatible, which makes it disproportionately valuable in trauma situations where doctors don’t have time to type a patient’s blood. Many blood banks will contact AB negative donors directly when supplies run low.
For your own health, knowing your type matters most in emergencies and during pregnancy. Wearing a medical ID bracelet or keeping your blood type in your phone’s emergency information can speed up treatment if you’re ever unable to communicate. In non-emergency situations, hospitals will always type and crossmatch your blood before a transfusion regardless of what you tell them, so there’s no risk of a mix-up from self-reporting.