Blood Type Compatibility Checker
Check blood type compatibility for transfusion and donation. Select your blood type to see who you can donate to and receive from. Based on ABO and Rh factor compatibility rules. Free and private.
Select Your Blood Type
Full Compatibility Chart
| Blood Type | Can Donate To | Can Receive From |
|---|---|---|
| O− | All types | O− |
| O+ | O+, A+, B+, AB+ | O+, O− |
| A− | A−, A+, AB−, AB+ | A−, O− |
| A+ | A+, AB+ | A+, A−, O+, O− |
| B− | B−, B+, AB−, AB+ | B−, O− |
| B+ | B+, AB+ | B+, B−, O+, O− |
| AB− | AB−, AB+ | A−, B−, AB−, O− |
| AB+ | AB+ | All types |
How Blood Type Compatibility Works
Blood type compatibility depends on two systems: ABO (A, B, AB, O) and Rh factor (positive or negative). When receiving a transfusion, the donor's blood must be compatible with the recipient's — incompatible blood can cause a serious immune reaction. The ABO system determines which antigens are on your red blood cells, while the Rh factor indicates the presence of the D antigen.
Key Blood Type Facts
Universal Donor: O− can donate red blood cells to anyone
Universal Recipient: AB+ can receive red blood cells from anyone
Most Common: O+ is the most common blood type globally (~37%)
Rarest: AB− is the rarest blood type (~1%)
ABO Blood Group System
Your ABO blood type is determined by antigens on your red blood cells. Type A has A antigens, Type B has B antigens, Type AB has both, and Type O has neither. Your plasma contains antibodies against the antigens you lack — this is why mismatched transfusions are dangerous. Your body attacks foreign antigens.
Why Blood Type Compatibility Matters
Receiving incompatible blood triggers an immune response where antibodies attack foreign red blood cells, causing them to clump (agglutination). This can lead to kidney failure, shock, and even death. That's why blood banks carefully cross-match blood before every transfusion. Knowing your blood type is essential for emergency preparedness.
Blood Type and Pregnancy
Rh compatibility is important during pregnancy. If an Rh-negative mother carries an Rh-positive baby, her body may produce antibodies against the baby's blood cells (Rh incompatibility). This is managed with RhoGAM injections. ABO incompatibility between mother and baby is usually less severe but can cause mild jaundice in newborns.
How to Interpret Your Results
Review all sections of the analysis, not just the overall score. Focus on actionable items — findings you can actually change or improve. Run the check multiple times with different inputs if you want to compare scenarios. Keep in mind that automated analysis provides a useful starting point, but may not capture every nuance of your specific situation. Use the results as guidance for improvement rather than a definitive verdict.
Frequently Asked Questions
What is the universal blood donor type?
O negative (O−) is the universal red blood cell donor. O− red blood cells can be transfused to patients of any blood type, making it critical for emergency situations when there is no time to determine the patient's blood type.
What is the universal blood recipient?
AB positive (AB+) is the universal recipient for red blood cells. People with AB+ blood can receive red blood cells from any ABO and Rh type. However, AB+ individuals can only donate red blood cells to other AB+ recipients.
Can Rh-positive blood be given to Rh-negative patients?
Generally no. Giving Rh-positive blood to an Rh-negative patient can cause the recipient to develop anti-Rh antibodies, which could cause serious reactions in future transfusions. Rh-negative patients should receive Rh-negative blood whenever possible.
What is the rarest blood type?
AB negative (AB−) is the rarest of the eight main blood types, found in approximately 1% of the population. The Bombay blood group (hh) is even rarer but not part of the standard ABO system.
How is blood type inherited?
Blood type is inherited from your parents. The ABO gene has three alleles: A, B, and O. A and B are codominant (both expressed), while O is recessive. The Rh factor is determined by a separate gene — positive (Rh+) is dominant over negative (Rh−).
Is my data private?
Yes. This tool runs entirely in your browser. No blood type data or personal information is sent to any server.