Blood Type Compatibility Checker
Check blood transfusion and donation compatibility between blood types. ABO and Rh factor guide.
Quick Reference 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+ | AB-,A-,B-,O- |
| AB+ | AB+ | All types |
About this calculator
Blood type compatibility decides who can safely give blood to whom. Choose a donor's blood group and a recipient's, and this tool tells you whether red blood cell transfusion between them is compatible, with the reason.
The system rests on two things: the A and B antigens on red cells, and the Rh factor. A person's immune system attacks antigens it does not have, so type O red cells, with no A or B antigens, can go to anyone (O negative is the universal donor), and AB positive recipients can receive any type.
How to use it
- Select the Donor blood type.
- Select the Recipient blood type.
- Read whether the match is compatible and why.
The compatibility rules
For red cells: type O donates to O, A, B and AB; type A donates to A and AB; type B donates to B and AB; type AB donates to AB only. Rh negative donors can give to both Rh negative and positive recipients, but Rh positive donors can give only to Rh positive recipients. Plasma compatibility runs the opposite way: AB plasma is the universal plasma donor.
Worked example
O negative donor to AB positive recipient
| Result | Compatible |
| Why | O negative red cells carry no A, B or Rh antigens, so the recipient's immune system has nothing to attack |
The reverse, AB positive donating to an O negative recipient, would be incompatible and dangerous.
This tool gives general information, not medical advice. Talk to a doctor before making health decisions.
Tips and common mistakes
- Know your own blood type and keep a record. It is useful in emergencies.
- In an emergency with an unknown type, hospitals use O negative red cells.
- Rh negative women who are pregnant may need anti-D injections if the baby is Rh positive. Ask your doctor.
- Regular donation is possible every three months for men and four for women, subject to health checks.
- Hospitals always cross-match blood before a transfusion. This tool is educational.
Frequently asked questions
Who is the universal donor?
O negative for red blood cells.
Who is the universal recipient?
AB positive, who can receive red cells of any type.
Which blood type is rarest?
AB negative is the rarest in most populations; in India, B positive and O positive are the most common.
Does the Rh factor matter?
Yes. Rh positive blood given to an Rh negative recipient can trigger an immune response.
Can I give blood to my family?
Only if the types are compatible, and after screening.
Is this a substitute for a lab test?
No. Hospitals test and cross-match every unit.