Blood Type Compatibility Calculator
Check blood type compatibility for transfusion and Rh in pregnancy.
Tip: Group O− is the universal donor; AB+ is the universal recipient. Rh-negative → risk in pregnancy if the child is Rh+.
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About this digital tool
The blood type compatibility checker shows whether a donor's blood is compatible with a recipient's, according to the ABO system and the Rh factor (positive or negative). Choose the donor's and the recipient's group and Rh and instantly get the answer: compatible or not.
Under the basic rules, O negative is considered the universal donor and AB positive the universal recipient. The Rh factor matters in pregnancy too: if the mother is Rh negative and the child Rh positive, the doctor may recommend protection to avoid complications in future pregnancies. This tool is for information only. Transfusions and medical decisions are made only by healthcare staff after laboratory tests.
How to use
- Choose the donor's blood group (A, B, AB or O).
- Choose the donor's Rh factor (positive or negative).
- Choose the recipient's blood group.
- Choose the recipient's Rh factor.
- See whether the result is compatible and consult a doctor for any medical decision.
Frequently asked questions
Why does the Rh factor matter in pregnancy?
If the mother is Rh− and the child Rh+, the mother's body can produce antibodies. An anti-D injection (RhoGAM) prevents complications.
Which blood group is the universal donor?
O negative (O−) is considered the universal donor for red cells, because it has no A, B or Rh antigens. In practice, hospitals still carry out compatibility tests.
Which blood group is the universal recipient?
AB positive (AB+) can receive red cells from all ABO and Rh groups. Here too the decision is taken by the medical team.
Can I use this tool to decide on a transfusion?
No. Transfusions require laboratory testing and a doctor's decision. This tool is for education only.