Well-Being Medical Advances

Scientists find new set of blood types 

They identify five versions of an antigen on the surface of red blood cells.

Story at a glance


  • Blood type matching is important for blood transfusions.

  • Health complications can arise when blood types are incompatible. 

  • Scientists describe a new blood type group named Er. 

Everyone should know their blood type in case of a life-threatening event that results in a need for a blood transfusion. A new discovery introduces a new group of blood types that may be important to be aware of in rare occasions. 

A group of scientists have described a newly discovered blood group. Besides the most commonly known blood type groups like A, B, O and Rh, there are dozens of others. This new group, named the Er blood group, is the 44th such blood group to be described. 

In total, there are five Er antigens in this group based on genetic variations in the Piezo1 protein, according to the study published in the journal Blood. The Piezo1 protein is found on the surfaces of red blood cells. 

Antibodies that match the Er antigens can attach to them and lead to immune cells attacking the mismatched cells. This can also happen in other cases where blood types are incompatible and why doctors and health care practitioners work to avoid mismatches. 

The Er antigen was discovered years ago, but this study is the first to describe different mutations of the antigen. This includes two versions of the antigen that were previously unknown. 

“Discovering a new blood group system is like discovering a new planet. It enlarges the landscape of our reality,” said Daniela Hermelin, from the Saint Louis University School of Medicine, to WIRED. Hermelin was not involved with the study.

Differences in Er group compatibility may be rare but could be important for physicians and nurses to pay attention to if they are having trouble diagnosing their patient.