Rhnull Blood

Rhnull blood, often called “golden blood,” is the rarest blood type in the world. Fewer than 50 individuals globally are known to have it, making it incredibly valuable—especially for transfusions among people with rare blood types.

This blood type is defined by a complete absence of all Rh antigens on the red blood cells. While most people have one or more Rh antigens (like D, C, c, E, e), individuals with Rhnull blood lack all of them. This condition can occur due to mutations in genes that regulate Rh antigen expression and is typically inherited in an autosomal recessive manner—both parents must carry the genetic trait.

Because Rhnull blood is so rare, donors and recipients are extremely hard to match. However, it can be universally accepted by people with other rare Rh-deficient blood types, making it a potential “universal donor” in rare cases.

Key facts about Rhnull blood:

Frequency: Estimated at ~1 in 6 million people.

Risks: Individuals with Rhnull blood may experience hemolytic anemia and may be at higher risk during surgeries or injuries due to limited transfusion options.

Genetics: Inherited when both parents pass on a nonfunctional RH gene.

Medical professionals closely monitor Rhnull blood donors, often storing their blood for emergencies. Due to its rarity and clinical importance, Rhnull blood is managed through international rare donor registries.