“The golden (Rh null) blood is the rarest blood group, lacking Rh antigens in the red blood cells (RBCs). Learn more about the golden blood type, other rare blood types, and blood charts.

Proteins known as Rhesus (Rh) factors or antigens are completely absent in the red cells of people with the golden blood type or Rh null blood group. This is the rarest blood group in the world, with less than 50 individuals having this blood group. Golden blood type was first discovered in an Australian Aboriginal woman in 1961.

Our red blood cells have sugars and proteins called antigens on their surface membranes. Depending on the mix of antigens present, blood is categorized into different blood types, and we have A, B, O, or AB blood types. The ABO system has a further distinction as Rh-positive or Rh-negative depending on the presence or absence of the “Rh-D” factor in the cells.

A person with the golden blood type, or the Rh null blood type lacks all the Rh antigens whereas a person with the Rh-negative blood group lacks only Rh-D antigen.

The worry with the golden blood type is that donations of the Rh null blood type are incredibly scarce and difficult to obtain. An Rh null person has to rely on the cooperation of a small network of regular Rh null donors around the world if they need blood. Across the globe, there are only nine active donors for this blood group. This makes it the world’s most precious blood type, hence the name “golden” blood.

Golden blood type can be donated. Because of the absence of antigens on RBCs, a person with Rh null blood is considered to be a universal donor, and this blood can be donated to anyone with rare blood types within the Rh systems.”

Medicine Net (Golden Blood Type: Understanding the Rarest Blood Group)