What are the three rarest blood types?

The Rarest Blood Types in the United States

While most people know whether they’re A, B, AB, or O, few realize just how rare certain blood types truly are. In the United States, the rarest of them all is AB negative (AB-), found in only 0.6% of the population. That means just 6 out of every 1,000 people carry this blood type, making it incredibly scarce—and highly valuable in medical settings, especially for plasma donations.

Right behind AB- is B negative (B-), present in about 1.5% of Americans. Though slightly more common than AB-, B- is still considered rare and is particularly in demand for pediatric care and emergency transfusions. Its scarcity becomes even more pronounced in certain ethnic populations where the type is even less frequent.

The third rarest is AB positive (AB+), which might come as a surprise since it’s more widely recognized. Still, it’s found in only 3.4% of people—less than one in 30. AB+ plays a unique role: those with this blood type can receive red blood cells from any group, making them universal recipients, but they can only donate to other AB+ individuals, which limits their impact unless carefully matched.

Understanding blood type rarity isn’t just trivia—it’s crucial for hospitals managing blood supplies and for patients in need of rare matches. Donors with AB- or B- are especially encouraged to give, as their contributions can save lives in situations where alternatives are nearly nonexistent. Simply knowing your blood type—and donating when possible—can make a real difference.