The rarest blood type, AB negative, is the most common. O positive is the most frequent. The American Red Cross has provided a breakdown of rare and common blood types based on ethnicity.
47% of African-Americans are African-American
Caucasian - 2%
Asians - 7%
What determines the blood type?
According to the National Institutes of Health, a person's blood type can be determined by whether they have antigens molecules on the surface of red blood cells. The "A antigen" (or "B antigen") are the two main antigens that are used in blood typing. Type A blood has A antigens in their red blood cells, while type B blood has only B antigens. Type AB blood has both, while type O blood does not.
The "Rh factor", also known as "Rhesus", is another protein that red blood cells can have. If a person has the Rh protein in their red blood cells, it is considered "positive", and "negative" otherwise.
Is blood type genetic?
According to the Red Cross, yes, a person's genetic blood type can be inherited from their parents.
Transfusions and blood type
Because certain antigens in blood cells can cause an immune system reaction that could attack donated blood, blood typing is especially important for blood transfusions.
The Red Cross states that Rh-negative people can only receive Rh negative blood. However, Rh-positive people can receive Rh positive or Rh-negative blood.
Type A blood can also be used to transfuse patients with type A, type AB or type A blood. Patients with type B blood or type AB can use type B blood. Patients with type B blood or type AB can use type B blood. Patients with type AB can use type AB for their blood. Patients with type A, type B or type AB blood can use type O blood.
Which blood type is the "universal donate"?
Because this blood type is compatible with all blood types, it's called "universal donor".
According to the Red Cross, Type O blood is frequently in short supply in hospitals due to high demand for this universal donor type. Type O-negative blood, which is the most commonly used in emergencies when it may not be possible to determine a patient’s blood type, is particularly in high demand.
What are the "rare" blood types?
ABO and Rh are the most important blood types for transfusions. However, hundreds of antigens have been discovered on the surface red blood cells of people. According to the Cleveland Clinic, a person's blood type can be classified as rare if they have a blood type that is not common or lacks an antigen. Rare blood types, in particular, are those found in fewer than 1 in 1000 people.
The Cleveland Clinic says that "Rh-null" is one of the most rare blood types in the globe. This blood type has been identified in fewer than 50 people around the world, earning it the title "golden blood".
Are blood types susceptible to change?
The blood type of a person does not change. It stays the same throughout their lives. According to the Cleveland Clinic, there are rare instances when blood type can change. This includes bone marrow transplants, and people with certain cancers or infections.
Pregnancy and blood type
If the mother is Rh negative, the fetus can inherit the Rh factor from the father. The Rh factor can be passed on to the fetus from the father or mother. This is because the mother's immune system may react to "positive" blood. Pregnant women should have their blood type tested. According to the Cleveland Clinic, Rh-negative people can receive Rh immunoglobulin to treat a potentially dangerous immune reaction.
How to determine your blood type
You can ask your doctor if they have a record if your blood type is not known. CNN reports that if they don't have a record, you might be able request blood typing when you next get your blood drawn. According to the Cleveland Clinic, you can also determine your blood type by donating blood. You can also get your blood type through at-home tests.
The American Red Cross has more information about blood types and donor options.
. The Cleveland Clinic has more information about blood types and health.
. Learn more about rare blood types from the U.K. National Health Service
This article is intended to provide information only and does not constitute medical advice. Rachael Rettner updated this article on September 10, 2021.