Blood Type Compatibility Calculator

How the Blood Type Compatibility Calculator Works

Select your ABO/Rh blood type to instantly see which blood types you can donate red blood cells to and receive from. The calculator also displays a full compatibility matrix showing all possible donor-recipient combinations, along with your antigen profile, antibody information, Rh factor, and population frequency. Special notes highlight universal donor and recipient status.

Blood type compatibility is determined by the antigens present on red blood cells and the antibodies in plasma. When incompatible blood is transfused, the recipient's antibodies attack the donor's red blood cells, causing a potentially life-threatening hemolytic transfusion reaction. Understanding compatibility is crucial for safe blood transfusions and organ transplants.

The ABO Blood Group System

The ABO system classifies blood into four groups based on antigens: Type A (A antigens, anti-B antibodies), Type B (B antigens, anti-A antibodies), Type AB (A and B antigens, no ABO antibodies), and Type O (no ABO antigens, anti-A and anti-B antibodies). The Rh system adds a positive or negative designation based on the D antigen, creating eight common blood types.

Universal Donors and Recipients

O-negative blood is the universal donor for red blood cells because it has no A, B, or Rh antigens to trigger immune reactions. AB-positive is the universal recipient because it has all antigens and will not produce antibodies against any donated blood type. For plasma transfusions, the compatibility is reversed: AB plasma is universal donor plasma because it contains no ABO antibodies.

Blood Type and Population Distribution

O-positive is the most common blood type in the United States at 37.4%, followed by A-positive at 35.7%. The rarest type is AB-negative at just 0.6%. Blood type distribution varies significantly by ethnicity: Type O is more common in Hispanic and African American populations, while Type A is more common in European populations.

Frequently Asked Questions

What is the universal donor blood type?

O-negative is the universal donor for red blood cells. It can be transfused to any patient regardless of their blood type.

What is the universal recipient?

AB-positive can receive red blood cells from all eight blood types because it has all antigens present.

How is blood type determined?

By the presence of A and B antigens on red blood cells and the Rh factor (D antigen). Blood type is inherited and does not change.

Can blood types affect pregnancy?

Rh incompatibility can occur when an Rh-negative mother carries an Rh-positive baby, potentially causing hemolytic disease. This is prevented with RhoGAM injections.

What is the rarest blood type?

AB-negative is the rarest at 0.6% of the population. O-positive is the most common at 37.4%.