Versiti - Rare and Uncommon Blood Types | Blood Types Explained
Sarah - Rare and Uncommon Donor

Rare and Uncommon Blood Type Facts

Did you know? Facts about the 35+ other blood groups and 600+ other antigens besides A and B.

Rare and Uncommon Blood Types Explained: Everything You Need to Know About Inherited Genetic Differences

Having a rare or uncommon blood type doesn’t mean your blood is better or worse—it’s just a genetic difference. But it DOES mean you are extremely special!

You’ve likely heard of the common blood groups: A, B, AB and O. But did you know? Besides these common blood groups, there are over 35 other blood groups and over 600 other known antigens. The unique mix of proteins and sugars (antigens) present on your red cells, which you inherited from your biological parents, determines your extended blood type and whether you fall into one of these rare and uncommon blood groups.

One of these uncommon blood types is the Ro blood type, which is invaluable for patients with sickle cell disease. Click to learn more about Ro blood donors and sickle cell disease.


The Rarest and Most Uncommon Blood Types By Ethnicity

Oftentimes, patients experience the best outcomes when they receive lifesaving donations from individuals of similar ethnic backgrounds. When you donate, your blood donation will be put to good use, likely saving someone else from your community in need of a lifesaving transfusion.    

So, what’s your blood type? Don’t know? That’s okay! 66% of Americans don’t know their blood type! Simply donate blood and we will tell you after your first successful donation!

Right now, a local hospital patient who shares your rare or uncommon blood type is counting on your donation.


“Blood transfusions helped to bring me back to life.”

Sarah - Rare and Uncommon Donor

Every day, patients in your community need blood transfusions to survive and thrive. They rely on the generosity of donors like you, who help ensure a safe, healthy blood supply. Make an appointment to donate blood today.

Explore donation opportunities in Illinois, Indiana, Michigan, and Ohio.

Blood Donation Locations
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Host A Blood Drive
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Types of Donations
Volunteer to donate blood at a blood donation center near you. Find out how often you can donate blood and make an appointment to donate today.

Rare Blood Donors

Please continue to donate regularly. We get many requests each day for patients across the country who are in immediate need of blood. If we have blood available in our inventory, we can ship it the same day.

No. A person with a rare blood type does not have better or worse blood - it is just a genetic difference. And it means you are extremely special!

Yes, especially your brothers and sisters. Please encourage them to donate also.

The term “rare” means that the type occurs in only a few people. Some rare types only occur in 1 in 5000 people. Many rare types are unique to specific populations. For example, Vel negative blood is more common in Caucasians while U negative blood is more commonly found in African Americans.

Versiti Blood Center of Wisconsin will contact you occasionally to update your address. We may also contact you to donate if we receive a request for your rare blood type and have no available units.

Versiti will notify ARDP that we are registering a donor, for example, that is O Positive and U Negative. If another blood center needs O Positive U Negative blood, ARDP can check their database and see that we have a donor registered with that type. They will then contact us to see if we have blood available or can call a donor to donate.

If you donate blood and we do not have any requests for your type, your donation is frozen for use in the future. Blood can be specially frozen for up to 10 years.

A Versiti staff member will be glad to help you. Please call 414-937-6205.

ARDP is the American Rare Donor Program. It is based in Philadelphia where they maintain a nationwide database of rare donors.

Because some blood types are so rare, your donation may be somebody's only hope for survival. Patients who need frequent transfusions because of certain diseases such as sickle cell disease, leukemia and other cancers are especially at risk.

No. Versiti only provides ARDP with your blood type and donor number. No personal information is provided.

Ro Blood Donors

No, Ro characteristics on blood cells are not abnormal and perform normally. Ro does not mean that you have sickle cell.

The vast majority of blood recipients have no trouble. Patients on chronic transfusions, like those with Sickle Cell Disease, are at a higher risk for developing issues if more specifically matched blood is not available.

Perhaps, like all blood types Ro is inherited from your parents. There is a significant chance that others in your family also have this special type.

Versiti tests every donor’s blood to find the best matches for patients. This is how we ensure an ample blood supply for hospitals and patients. After donating, if your blood has Ro characteristics, Versiti may contact you to let you know your blood is very needed.

Ideally, three or more donations a year. Sickle Cell Disease patients reliant on transfusion require 8-10 units per month. That means they rely on 8-10 donors a month for one treatment. You are invaluable to these patients!

It is a normal blood type that is specially found in only 4% of our current donors.

They don’t express specific proteins that make their blood a safer transfusion for those with sickle cell disease.

Versiti supplies sickle cell disease programs locally and nationally, your blood will be sent to the patient that needs it most.

Sickle Cell Disease

All blood types – but especially the uncommon blood type Ro. Since sickle cell patients are transfused so frequently, they need blood that is specially typed for them. The Ro sub-type makes up only about 3% of all donated blood, but 44% of patients with sickle cell disease have this type.

If you have sickle cell disease, you are not able to donate blood. But if you have sickle cell trait, you are still able to donate blood.  Some donors may by directed away from whole blood donations and should consider platelet or plasma donation.

  • SCD is inherited in the same way that people get the color of their eyes, skin and hair.
  • A person with SCD is born with it.
  • People cannot “catch” SCD from being around a person who has it.

  • Sickle cell disease (SCD) is a group of inherited red blood cell disorders.
  • Healthy red blood cells are round and they move through small blood vessels carrying oxygen to all parts of the body.
  • For someone with SCD, the red blood cells become hard and sticky and look like a C-shaped farm tool called a “sickle.”
  • Sickle cells die early in comparison to non-sickle cells, which causes a constant shortage of red blood cells.
  • Sickle cells can get stuck in small blood vessels and block the flow of blood and oxygen to organs in the body. These changes in cells can cause repeated episodes of severe pain, organ damage, serious infections or even stroke.
  • Although there is no cure for sickle cell disease, blood transfusions (supplied exclusively by volunteer blood donors like you!) are a critical part of treatment. 
  • Many times, only blood transfusions can relieve the pain and complications that occur during a sickle cell episode. 
  • Blood that closely matches that of a patient is less likely to be rejected by the patient and can mean fewer complications after a transfusion.

  • It is estimated that SCD affects 90,000 to 100,000 people in the United States, mainly people of African descent.
  • The disease occurs among about 1 of every 365 births of African descent and among about 1 of every 36,000 births of Hispanic descent.
  • SCD affects millions of people throughout the world and is particularly common among those whose ancestors come from sub-Saharan Africa; regions in the Western Hemisphere (South America, the Caribbean and Central America); Saudi Arabia; India; and Mediterranean countries such as Turkey, Greece and Italy.

For more of the science behind blood and blood types, visit the AABB (Association for the Advancement of Blood & Biotherapies) website

Ro Blood Type
Volunteer to donate Ro blood type at a blood donation center near you. Learn how rare Ro blood is and make an appointment to donate Ro blood today.
Blood Types Explained
Find the facts about different blood types, from A+ to O-. Learn more about why people have different blood types before your next blood donation.
Types of Donations
Volunteer to donate blood at a blood donation center near you. Find out how often you can donate blood and make an appointment to donate today.
Importance of Diverse Donors
Diverse blood donations improve blood transfusion outcomes for sickle cell patients and diverse blood recipients. Make an appointment to donate blood.