What blood type is the universal donor?

O negative is the universal red blood cell donor, meaning it can be given to patients of any blood type in emergencies. However, O negative is relatively uncommon at about 7% of the population, creating constant demand at blood banks.

Does blood type affect health?

Research suggests correlations between blood type and certain health conditions. Type O may have lower risk of heart disease but higher risk of stomach ulcers. Type A may be associated with slightly higher cancer risk. However, lifestyle factors have far greater impact than blood type.

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🩸 What Is the Rarest Blood Type? All 8 Types Ranked

Q: What is the rarest blood type?

AB negative is the rarest of the eight common blood types, found in less than 1% of the global population. The extremely rare Rhnull blood type (sometimes called 'golden blood') is found in fewer than 50 people worldwide.

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AB-

Rarest type

0.6%

🩸

B-

Very rare

1.5%

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AB+

Uncommon

3.4%

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O+

Most common

37.4%

📊 All 8 Blood Types Ranked

37.4%

O+

35.7%

A+

8.5%

B+

6.6%

O-

6.3%

A-

3.4%

AB+

1.5%

B-

0.6%

AB-

🔬 Why AB- Is So Rare

AB- requires both A and B antigens (already uncommon together) plus a negative Rh factor. Only about 1 in 167 people have this combination. Despite its rarity, AB- individuals are universal plasma donors.

🌍 The Bombay Blood Group

Even rarer than AB- is the Bombay phenotype (hh), found in roughly 1 in 250,000 people globally (more common in South Asia at ~1 in 10,000). These individuals can only receive blood from other Bombay-type donors.

🗺️ Regional Variations

Blood type distribution varies dramatically by region. Type B is most common in Central and East Asia (~25%), while Type O dominates in Central and South America (~70% in some indigenous populations). Rh-negative blood is most frequent in the Basque region of Spain/France (~30%), but nearly absent in East Asian populations (<1%).

💎 Explore More Rarity Guides