O Negative (O−)

O Negative blood has no A or B antigens and lacks the Rh factor, making it the universal donor type used in emergencies.

Key Characteristics

• Has no A or B antigens on red blood cells.
• Lacks Rh factor (Rh negative).
• Represents about 7% of people globally.

Compatibility

Can donate to anyone, but can only receive O− blood.

Why It Matters

O− is the universal donor — always used in trauma care and neonatal units when the recipient’s type is unknown.

Health & Donation Tips

• Donate as often as possible — you save lives in every emergency.
• Maintain healthy iron and hydration levels.
• Encourage others to check if they’re O− and become regular donors.