What Is a Blood Group Test?
A blood group test determines which ABO blood group and Rh (Rhesus) type you belong to. Your blood group is determined by the presence or absence of specific antigens (proteins and sugars) on the surface of your red blood cells. These antigens are inherited from your parents and remain constant throughout your life.
There are four main ABO blood groups: A, B, AB, and O. Each can be either Rh-positive (+) or Rh-negative (−), giving eight main blood types: A+, A−, B+, B−, AB+, AB−, O+, and O−. Knowing your blood type is essential for blood transfusions, organ transplantation, and pregnancy management.
Why Is Blood Group Testing Important?
- Essential before any blood transfusion to prevent potentially fatal transfusion reactions
- Required before surgery in case a transfusion is needed
- Important during pregnancy — Rh-negative mothers carrying Rh-positive babies may develop antibodies
- Required for organ and tissue transplantation compatibility
- Useful personal health information for emergencies
- May influence disease risk — some studies link blood type to cardiovascular disease and cancer risk
The ABO Blood Group System
| Blood Type | Antigens on Red Cells | Antibodies in Plasma | Can Receive From | UK Prevalence |
|---|---|---|---|---|
| O | None | Anti-A, Anti-B | O only | 44% |
| A | A antigen | Anti-B | A, O | 42% |
| B | B antigen | Anti-A | B, O | 10% |
| AB | A and B antigens | None | A, B, AB, O | 4% |
The Rh Blood Group System
The Rh system is determined by the presence (Rh+) or absence (Rh−) of the D antigen on red blood cells. In the UK, approximately 85% of people are Rh-positive and 15% are Rh-negative.
Rh in pregnancy: If an Rh-negative mother carries an Rh-positive baby, her immune system may produce anti-D antibodies that could attack the baby's red blood cells in subsequent pregnancies (haemolytic disease of the newborn). This is prevented by routine anti-D immunoglobulin injections during pregnancy.
Blood Type and Health
Research has identified some associations between blood type and disease risk:
- Type O: Lower risk of heart disease, stroke, and venous thromboembolism; slightly higher risk of stomach ulcers (H. pylori affinity) and cholera
- Type A: Slightly higher risk of coronary heart disease and stomach cancer; associated with higher LDL cholesterol
- Type B: Slightly higher risk of pancreatic cancer and type 2 diabetes
- Type AB: Highest risk of cognitive decline and dementia in some studies; highest risk of venous thromboembolism
- Non-O types: 60–80% higher risk of blood clots compared to type O
These are statistical associations, not deterministic outcomes. Lifestyle factors have a far greater impact on health than blood type.
Universal Donors and Recipients
- O− (universal red cell donor): Can donate red cells to any blood type — critical for emergency transfusions
- AB+ (universal recipient): Can receive red cells from any blood type
- AB− (universal plasma donor): Plasma from AB donors can be given to any blood type
When Should You Get Tested?
- You don't know your blood type and want it on record for emergencies
- You are planning pregnancy — particularly important if you may be Rh-negative
- You are preparing for surgery
- You want to donate blood (blood group will be determined at your first donation)
- You are curious about potential health associations with your blood type
Check Your Blood Group Test Levels at Home
The Core Health 45 includes Blood Group Test testing along with 44 other biomarkers. Results in 2 working days with a free at-home phlebotomist visit.
View Core Health 45 →Which Lola Health Tests Include Blood Group?
Blood group testing is available as an add-on biomarker with Lola Health tests:
- Browse All Blood Tests — add blood group typing to any comprehensive panel
Find Out Your Blood Type
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At-Home Blood Testing
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