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How Do Blood Types Work? 

Sara Martinez 
January 1, 2024 

Who discovered blood types?

In 1930 Dr. Karl Landsteiner won the Nobel Prize in Physiology & Medicine for his discovery of human blood types. He was the first to classify human blood groups into A, B, AB, and O types. His work made safe blood transfusions possible and transformed the medical industry.

How do blood types work?

Although all blood has the same basic components, not everyone has the same blood type. Your blood type is determined by your ABO type and a negative or positive Rh factor. There are eight common blood types (A+, A-, B+, B-, AB+, AB-, O+, and O-) and many rare ones.

Just like eye color, your blood type is passed genetically from your parents. You inherit a gene from each parent so your blood type may not be the same as your parents.

For example:

  • If you inherit an A gene from your father and an A gene from your mother, you will either have type A or O blood.
  • Type B from one parent and type B or type O gene from the other parent will give you either type B or O blood.
  • But inherit an A gene from one parent and a B from the other and you could have A, B, AB, or O type blood.
  • Those with type O blood have inherited the O gene from each parent.
how blood types work chart father mother child

Child’s Blood Type Chart

The Rh factor works in a similar manner. Your Rh factor is determined by whether or not your blood contains a specific protein. If you have it, you are positive. If you don’t have it, you are negative.  

  • If both your parents are Rh negative, you are probably Rh negative.
  • If either parent is Rh positive, you could be either Rh negative or Rh positive.
rh factor blood type chart

Child’s Rh Factor Chart

How can I find out my blood type?

A simple blood test can determine your blood type. Your doctor can do this or your blood may be tested if you undergo a medical procedure.

But there is an easier way to learn your blood type – by donating blood!

When you donate blood, your donation will be tested and typed. Your blood type information will be available to you after your donation, along with your free wellness checkup stats like your blood pressure and overall cholesterol level.

Make your appointment to donate blood and find out your blood type today!

You don’t have to know your blood type in order to donate.

Blood type is important because a blood donation must be compatible with a recipient. If it is an incompatible type, the body will reject the blood during a transfusion.

However, you can donate without knowing your type! OneBlood tests all donated blood to determine the type and to make sure patients receive the correct blood type.

Target Your Type®

Each blood type holds a unique power to save lives. OneBlood’s exclusive Target Your Type® program shows donors how to give the most needed components of their blood by targeting how they donate. 

Unlock the power of your blood type and save more lives! Find a blood drive near you to get started.

Sara Martinez, OneBlood Digital Marketing Specialist

Sara Martinez 

Sara Martinez is a Digital Marketing Specialist at OneBlood. From creating strategic online campaigns to writing engaging stories, she is passionate about raising awareness to inspire others and helping make a difference in our community. #ShareYourPower

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