Determine blood type compatibility for transfusion, calculate possible child blood types from parental genetics, and view population frequency data.
The ABO blood group system, discovered by Karl Landsteiner in 1901, classifies blood into four main types based on the presence or absence of A and B antigens on red blood cell surfaces: Type A, Type B, Type AB, and Type O. Combined with the Rh factor (positive or negative), this creates eight common blood types that determine transfusion compatibility and play a role in pregnancy management.
Understanding blood type compatibility is crucial for safe blood transfusions. Receiving incompatible blood can trigger a severe hemolytic transfusion reaction where the recipient's antibodies attack the donated red blood cells, potentially causing kidney failure, shock, and death. Type O-negative blood is the universal red cell donor (compatible with all types), while AB-positive is the universal recipient.
This calculator provides complete compatibility information for all eight blood types, showing which types you can safely donate to and receive from. It also includes a blood type inheritance calculator that determines possible blood types for children based on parental blood groups using Mendelian genetics. The tool displays population frequency data and a full 8×8 compatibility matrix for comprehensive reference.
This calculator provides instant blood type compatibility information for transfusion planning, helps prospective parents understand possible blood types for their children, and serves as an educational tool for understanding blood group genetics and population distribution.
This tool is designed for quick, accurate results without manual computation. Whether you are a student working through coursework, a professional verifying a result, or an educator preparing examples, accurate answers are always just a few keystrokes away.
ABO Compatibility: Type O has anti-A and anti-B antibodies, Type A has anti-B, Type B has anti-A, Type AB has neither. Donor RBCs must not carry antigens that the recipient has antibodies against. Rh: Rh− recipients should only receive Rh− blood.
Result: A+ can donate to A+ and AB+. Can receive from O−, O+, A−, A+. 35.7% of US population.
Type A+ blood carries A antigens and Rh factor. It can be given to A+ and AB+ recipients (who don't have anti-A antibodies and are Rh+). It can receive from any type that doesn't carry B antigens: O−, O+, A−, and A+.
Use consistent units throughout your calculation and verify all assumptions before treating the output as final. For professional or academic work, document your input values and any conversion standards used so results can be reproduced. Apply this calculator as part of a broader workflow, especially when the result feeds into a larger model or report.
Most mistakes come from mixed units, rounding too early, or misread labels. Recheck each final value before use. Pay close attention to sign conventions — positive and negative inputs often produce very different results. When working with multiple related calculations, keep intermediate values available so you can trace discrepancies back to their source.
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O-negative (O−) is the universal red cell donor because O cells lack A and B antigens, and Rh− is compatible with both Rh+ and Rh− recipients. However, O− is rare (6.6% of the population).
AB-positive (AB+) is the universal recipient for red blood cells because AB individuals have no anti-A or anti-B antibodies, and Rh+ can receive both Rh+ and Rh− blood. Use this as a practical reminder before finalizing the result.
No. Two type O parents (genotype OO × OO) can only produce type O children. All other ABO types require at least one A or B allele from at least one parent.
When an Rh− mother carries an Rh+ fetus, she may develop anti-Rh antibodies that could attack the fetus's red blood cells in subsequent pregnancies (hemolytic disease of the newborn). RhoGAM injection prevents this sensitization.
The ABO gene has three alleles: I^A, I^B, and i. A and B are co-dominant over O (i). Each person inherits one allele from each parent. Rh factor is determined by a separate gene (RHD).
AB-negative (AB−) is the rarest common blood type at about 0.6% of the US population. Some rare blood types outside the ABO/Rh system (like Rh-null) are even scarcer.