Your blood type is more than a letter and a sign. It’s a priceless gift for people in need of life-saving transfusions and the key to understanding your health better.
To learn your blood type, visit your primary care physician or simply ask when you donate blood. The AdventHealth network of care also includes numerous lab locations which can provide testing and pathology support at any stage of your health journey.
Understanding Blood Types
All blood consists of plasma, red and white blood cells and platelets, but your genes, which are passed down from your parents, dictate the antigens (protein markers) that you have. Blood types are classified as either A, B, AB or O, depending on the antigen.
Blood type groups include:
- Group A only has the A antigen on red cells (and B antibody in the plasma)
- Group B only has the B antigen on red cells (and A antibody in the plasma)
- Group AB has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
- Group O has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)
The positive or negative distinction in your blood type has to do with the Rhesus (Rh) factor, which can be present (+, or positive) or absent (-, or negative) in each group. If your blood is in group A, for instance, you could be type A-positive or type A, depending on whether your blood has the Rh factor.
Why You Should Know Your Blood Type
Blood is an incredible, essential component of your body. Knowing which of the eight blood types is at work inside your body is important for five distinct reasons and can help you stay healthy and even plan for the future.
To Get the Right Transfusion in an Emergency
The most important reason why you should know your blood type is in the case of an emergency. If you need a blood transfusion following an accident, surgery or delivery, you’ll need compatible blood. Blood antigens can trigger an immune response if they are foreign to your body, meaning an incorrect mix of blood can clump dangerously inside your veins.
Before a transfusion, your blood will be tested and matched with appropriate donor blood. If you should ever need a transfusion, our medical team will ensure you receive only what's compatible.
To Know Your Donor Type
One of the best reasons to know your blood type is to help others through blood donations. Sometimes, local organizations may put out a call for specific types, especially if there has been a natural disaster, tragedy or increase in traffic accidents. Types O-negative and O-positive are in high demand, most often.
Ideally, blood transfusions are done with donated blood that's an exact match for both type and Rh factor. However:
- Blood type AB-positive is the universal recipient and can receive blood from all types despite only being able to donate to other AB types
- Blood type O is commonly known as the universal donor because of its ability to supply red blood cells to nearly any recipient
- The universal plasma donor is a person who has type AB blood
- The universal red cell donor is someone who has type O blood
To Know How Common, or Rare, Your Blood Type Is
Your blood may be common or rare, depending on the antigens and Rh factor in your blood. In America, the most common blood type is O-positive, and the rarest is AB-negative.
Blood type O-positive tends to be the most common blood type across ethnic groups in the country, followed by A-positive blood. Because most of the American population has O-positive blood, the need for this type of blood donation is always high.
To Plan a Healthy Pregnancy
In some cases, blood type can influence fertility. Some research has shown that women who have type O blood may face a higher risk of a condition called diminished ovarian (egg) reserve, meaning it might be more difficult for these women to conceive. However, the fertility experts at AdventHealth can talk through concerns like this with you to help you better understand your personal fertility factors.
Women who want to have children, and those already pregnant, should know their blood types for another important reason: blood type or Rh factor incompatibility. If an expectant mother has Rh-negative blood and her baby has Rh-positive blood, it can lead to something called Rh incompatibility.
If the mother’s blood comes into contact with the baby’s during pregnancy — which is rare — it could trigger the mother’s blood to produce antibodies that attack the baby’s blood, which could result in jaundice for the baby.
Expectant mothers’ blood types are typically checked early in pregnancy to mitigate these conditions. If the mother’s blood type or Rh factor is different from her baby’s, she may receive an immunoglobulin shot, which helps prevent antibody production to keep mom and baby safe.
To Mitigate Health Conditions
Some blood types are linked to a higher risk of certain diseases. Scientists are constantly working to identify any correlations between blood type and disease risk.
For example, researchers at the Harvard School of Public Health looked at two long-term studies that assessed individuals heart health and blood type. The researchers found that:
- Participants with type B had a 10% higher risk of artery disease and type AB had a 23% higher risk
- People with type A blood were 5% more likely to develop coronary artery disease than those with type O
- Type O participants had the lowest risk of heart disease
Thanks to research, it’s also known that:
- People with type AB blood may have a higher risk of stroke
- Type A blood is a risk factor for stomach cancer
- Type 2 diabetes may not occur as often in people who have type O blood
Studies and statistics are always evolving, so it's worthwhile to know your specific blood type and use credible medical resources to stay informed of news about your blood type. When you understand the health conditions linked to your blood type, you can take health into your hands to mitigate other risk factors.
Blood Typing and Beyond at AdventHealth
Don’t know your blood type? Find out at your next doctor’s visit or when you donate blood.
Even if your current health needs don't include bloodwork, our lab teams of pathologists, medical technologists, medical technicians, pathology assistants and laboratory assistants can help with so much more. Take a look at our full range of laboratory services here.