Blood Groups:
The idea that blood type shapes personality did not start in Japan.Ancient Greek philosophers like Hippocrates and Aristotle first studied this concept. Later, a Japanese professor named Tokeji Furukawa grouped personalities by blood types. His research inspired over 200 other scientific papers on the topic.
Types of Blood groups
There are four primary blood types: A, B, A/B, and O.Your blood type is determined by genes inherited from your parents.
Whether your blood type is rare, common or somewhere in between, your donations are vital in helping save and improve lives.
What are the different blood types?
Everybody has a blood type. There are four major blood groups:
- 1.A
- 2.B
- 3.O
- 4.AB
These groups differ primarily on the presence or absence of antigens that can stimulate an immune response.
In addition to these four groups, a protein called Rh factor that may be either present (+) or absent (-) within each group. This further defines blood groups into eight common types:
O Negative Blood Group:
- Around 1 in 12 people have O negative blood
- About 13% of our blood donors are O negative.
- In comparison, 35% of donors have O positive blood.
- Air ambulances and emergency response vehicles carry O negative supplies for emergencies. Collecting enough O negative blood is a constant challenge and we always need your donations.
Who can receive O negative blood?
Everyone can receive O negative red blood cellsO negative donors are often called ‘universal donors’ because anyone can receive the red blood cells from their donations.
Although about 8% of the population has O negative blood, it accounts for around 13% of hospital requests for red blood cells.
What blood can O negative people receive?
Only O negative blood
People with O negative blood can only receive red cell donations from O negative donors.
Why is O negative blood important?
It’s used in emergencies
O negative blood is often called the ‘universal blood type’ because people of any blood type can receive it.
This makes it vitally important in an emergency or when a patient’s blood type is unknown.
AB positive blood type
Your blood type is determined by genes inherited from your parents.Whether your blood type is rare, common or somewhere in between, your donations are vital in helping save and improve lives.
How rare is AB positive blood?
1 in 50 donors is AB positive.Just 2% of donors have AB positive blood making it one of the rarest blood types in the country.
Who can receive AB positive blood?
Only AB positive people
AB positive red blood cells can only be used to treat people with AB positive blood.
What blood can AB positive people receive?
All blood types are safe
People with AB positive blood can safely receive red blood cells from any blood type. This means that demand for AB positive red blood cells is at its lowest level in a decade.
Why is AB positive blood important?
- It's rare.Although the need for AB positive red blood cells is falling, the demand for AB positive plasma hasn’t changed.
- To avoid wastage while ensuring the correct balance of plasma and red cells from AB positive donors, we manage donations differently to other blood types.
- Fresh frozen plasma is only produced from male donations.This is because female donors (especially those who have been pregnant) can develop antibodies that, while no danger to themselves, can prove life threatening to patients transfused with their plasma.
- We can generally meet the demand for frozen plasma and most red cells from our male donors, which is good news.
- We encourage our male donors to donate as frequently as possible but ask that female donors wait to donate until contacted directly by us.
- There are occasions when demand for AB positive rises.During these times we contact our female donors directly and rely on their support to ensure patients continue to receive the blood and blood products they need.
Your blood type is something you inherit, so it’s predetermined at birth. You cannot change your blood type later in life.
How common are different blood types?
Depending on your blood type, it might be easier or more difficult to find a potential partner with a compatible blood type. According to the Stanford School of Medicine, in the United States:
People with the blood type O+ represent about37.4% of the adult population.
People with the blood type O- represent about 6.6% of the adult population.
People with the blood type A+ represent about 35.7% of the adult population.
People with the blood type A- represent about 6.3% of the adult population.
People with the blood type B+ represent about 8.5% of the adult population.
People with the blood type B- represent about 1.5% of the adult population.
People with the blood type AB+ represent about 3.4% of the adult population.
People with the blood type AB- represent about 0.6% of the adult population.
Does blood type affect personality compatibility?
In Japan, there’s a blood type personality theory known as ketsueki-gata. The theory claims that blood types are an important indicator of a person’s personality. It was introduced in the 1920s by psychologist Tokeji Furukawa.
Ketsueki-gata suggests each blood type has specific personality traits:
Type A: well-organized
Type B: selfish
Type O: optimistic
Type AB: eccentric
Overview
How common are blood types: A breakdown of total population and ethnicity.
What are blood types?
A blood type is a classification system that allows healthcare providers to determine whether your blood is compatible or incompatible with someone else’s blood. There are four main blood types: A, B, AB and O. Blood bank specialists determine your blood type based on whether you have antigen A or B on your red blood cells. They also look for a protein called the Rh factor. They classify your blood type as positive (+) if you have this protein and negative (-) if you don’t.
This makes for eight common blood types:
A positive (A+).
A negative (A-).
B positive (B+).
B negative (B-).
AB positive (AB+).
AB negative (AB-).
O positive (O+).
O negative (O-).
Knowing about blood types allows healthcare providers to safely transfuse donated blood from one person into another during a blood transfusion. Blood types also need to be compatible for organ transplants.
How do blood types get determined?
Blood bank specialists determine blood types based on whether there are particular antigens on your red blood cells. An antigen is a substance that can make your body’s immune system react. Think of an antigen as a marker (like a nametag) that identifies a substance in your body as belonging or not belonging.
Your blood type is compatible with someone else’s if your immune system recognizes the antigens in donated blood as belonging.
What blood types mean
Most people think of A, B, AB and O when they hear the phrase “blood types.” These letters classify blood types based on whether red blood cells have the A antigen or B antigen. This is called the ABO system.
Type A: Red blood cells have the A antigen.
Type B: Red blood cells have the B antigen.
Type AB: Red blood cells have both A and B antigens.
Type O: Red blood cells have neither A nor B antigens.
Blood types are either “positive” or “negative,” depending on the absence or presence of the Rh factor’s D antigen, another marker. This is called the Rh system. Being RhD positive is more common than being RhD negative.
Positive (+): Red blood cells have the RhD antigen.
Negative (-): Red blood cells don’t have the RhD antigen.
Rare blood types
Outside of the ABO system, there are over 600 antigens that may attach to red blood cells. There are more than 30 different blood group systems related to these unique antigens. Other blood group systems include the:
Duffy blood group.
K antigen (or Kell) group.
Lutheran blood group.
Kidd blood group.
These blood groups are rare. A general definition of a rare blood type is one that happens at a rate of 1 per 1,000 people or fewer.
One of the world’s rarest blood types is Rh-null. Fewer than 50 people in the world have this blood type. It’s so rare that it’s sometimes called “golden blood.”
How are blood types inherited?
You inherit your blood type the same way you inherit your eye color — from your biological parents. Both the ABO genes and the Rh factors come from your parents. Due to the many possible combinations, you might not have the exact same blood type as your parents.
Which blood types are compatible?
An important part of blood donation is ensuring that someone receiving blood (recipient) has a compatible blood type with someone donating blood (donor). If you receive blood from a donor whose blood cells contain antigens your body doesn’t recognize, your immune system may attack the donated red blood cells. The results could be life-threatening.
Your blood type allows providers to determine which blood types are safe for you to receive. It helps them know which recipients can safely receive blood that you donate.
A positive: You can receive blood that’s A positive, A negative, O positive or O negative.
A negative: You can receive blood that’s A negative or O negative.
B positive: You can receive blood that’s B positive, B negative, O positive or O negative.
B negative: You can receive blood that’s B negative or O negative.
AB positive: You can receive any blood type.
AB negative: You can receive blood that’s AB negative, A negative, B negative or O negative.
O positive: You can receive blood that’s O positive or O negative.
O negative: You can only receive blood that’s O negative.
- Blood type A+ : Blood types you can receive A+, A-, O+, O-Blood types you can donate to A+, AB+
- Blood type A- :Blood types you can receive A-, O-Blood types you can donate to A-, A+, AB-, AB+
- Blood type B+ : Blood types you can receive B+, B-, O+, O-Blood types you can donate toB+, AB+
- Blood type B- : Blood types you can receive B-, O-Blood types you can donate toB-, B+ AB+, AB-
- Blood type AB+ : Blood types you can receive All blood types (universal recipient)Blood types you can donate toAB+
- Blood type AB- : Blood types you can receive AB-, A-, B-, O-Blood types you can donate toAB-, AB+
- Blood type O+ : Blood types you can receive O+, O-Blood types you can donate toO+, A+, B+, AB+
- Blood type O- : Blood types you can receive O-Blood types you can donate to All blood types (universal donor)
O-Negative: The Universal Donor
O-Negative blood is special because it doesn’t have A, B, or Rh antigens. This makes it safe for anyone to receive in urgent situations. We count on O-Negative donors to save lives when time is short.
AB-Positive: The Universal Recipient
AB-Positive people can get blood from any donor. This flexibility is why they’re so important in transfusions. We need a wide range of donors to help AB-Positive patients.
Note:
World Blood Donor Day is observed annually of June 14 to celebrate voluntary unpaid donors and raise awareness about the constant need for safe blood and plasma. The 2026 global theme is "One Drop of Humanity. Give Blood. Save Lives.