Which is the most common blood group : the most common blood group worldwide remains O-positive ($O^+$), representing approximately 38-40% of the global population. This is followed by A-positive ($A^+$) at around 27-30%.
However, there is a notable regional difference in India, where B-positive ($B^+$) is significantly more prevalent than in Western countries, often rivaling $O^+$ in specific areas.
Global vs. India Blood Group Distribution
| Blood Type | Global Frequency | India Frequency | Key Compatibility Role |
| O-positive ($O^+$) | ~38% | ~35% | Most common; can give to any $(+)$ type. |
| A-positive ($A^+$) | ~29% | ~22% | Second most common globally. |
| B-positive ($B^+$) | ~18% | ~32% | Significantly higher in South Asia. |
| O-negative ($O^-$) | ~7% | ~2% | Universal Donor for red blood cells. |
| AB-positive ($AB^+$) | ~3% | ~8% | Universal Recipient for red blood cells. |
The Rarest Blood Groups
While AB-negative ($AB^-$) is the rarest of the eight main types (occurring in less than 1% of people), it is not the rarest in existence:
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Rh-null (“Golden Blood”): The rarest blood type in the world. It lacks all Rh antigens and has been found in fewer than 50 people globally in history.
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Bombay Blood Group ($hh$): Extremely rare worldwide but found in about 1 in 10,000 individuals in India. People with this type can only receive blood from other Bombay Blood Group donors.
Why It Matters in 2026
With the India 2026 Census and updated health tracking, medical infrastructure is focusing heavily on $O^-$ and Bombay Blood registries. Because $O^+$ is so common, it is the most frequently used in hospitals, but $O^-$ remains the most critical for emergency transfusions when a patient’s blood type is unknown.
