When American Red Cross blood donor Alice Klundt donates blood, her contribution becomes a part of the American Rare Donor Program, which helps to supply hard-to-find blood products across the United States, and in some rare cases, to other countries across the world.

Alice’s blood type is O positive, but that’s just part of her blood’s story.

Red blood cells carry markers on their surface called antigens. These antigens are what determine a donor’s blood type.  This is the A, B and O types with which we are all familiar.  However, what you might not know is there are at least 600 other blood group antigens.

Alice is registered in the American Rare Donor Program because of the unusual combination of the most common red blood cell antigens not present on her red blood cells.  Her full blood type, called her RBC phenotype, is shared by only 0.42% of the world’s population — less than one half of one percent.

When a patient receives a blood transfusion, they can develop RBC antibodies to antigens missing on their red blood cells but are on the transfused blood.  This happens when the patient’s immune system recognizes the donor blood as foreign.  People who receive multiple transfusions are at a higher risk of developing these antibodies. Pregnancy also can increase the risk of developing antibodies to red cell antigens as the mother’s immune system reacts to the baby’s blood during gestation.

With some rare blood types, there may be few if any people in the area with the same rare blood type. In these situations, the American Rare Donor Program, and occasionally the international blood donor community, team up to find these exceedingly rare blood types. A child was recently determined to have only eight donor matches in the entire world.

Closer to home, one anemic woman in central Montana has been receiving multiple red blood cell transfusions every few weeks. The continued exposure to donor blood has caused her to develop five antibodies to common red cell antigens. These antibodies have reduced her potential donor pool to about 1 percent of the country.

Race can play a factor in blood typing, so maintaining a diverse donor pool is vital. The prevalence of some of these rare RBC antigens are associated with specific ethnicities. A hospital patient who needs a blood subtype RzRz, for example, relies mainly on Native American and Alaska Native donors.

The Duffy null blood type is found almost exclusively in the African-American community of donors.

The more people who donate red cells, the better chance of finding those with rare red blood cell phenotypes.

Piecing together the detailed blood profile is like working a “big puzzle,” said Wendy Palmer, Immunohematology Reference Laboratory supervisor with the American Red Cross laboratory in Great Falls. “It really is amazing to see it all come together.”

The science is constantly progressing, and the American Red Cross is adapting to the latest research. Technology has made a huge difference for people with rare blood types. Computerized registries keep track of which rare units are available across the country, or which donors need to be called in to provide their rare red blood cells.

If the patient’s red blood cells aren’t perfectly matched to these donors, or compatible with these donors, the body rejects the donor red cells or the white blood cells can attack the donor blood.  The recipient’s organs start working overtime and might even fail. The patient’s body may go into crisis immediately or soon after the transfusion.

People with rare blood can donate a stockpile for themselves if they are expecting surgery or a situation where a blood transfusion might be needed, such as giving birth. That’s what one area mother did. 

About 99.9 percent of people have Lan positive red blood cells, but this woman’s red blood cells are Lan negative. Following her physician’s advice, she prepared for her delivery by donating a pint of her own blood to be frozen and saved in case she should need a transfusion during delivery. The Red Cross also encouraged her family to be tested to identify any compatible donors.  This would allow them to help each other in a crisis requiring a rapid donation.

The Red Cross sends out letters to donors like Alice when they are determined to have a rare blood type, asking them to join the American Rare Donor Program Registry.

Alice, a Red Cross volunteer who lives in Great Falls, didn’t hesitate to say yes.

Her last blood donation went to help save a life in North Carolina. 

“Any time you can help someone, that’s a good thing,’’ she said. “Every pint helps.”