Quick answer
AB negative (AB−) means red blood cells carry both A and B antigens but not the RhD antigen. AB− red cells can generally be given to AB− and AB+ recipients, and AB− people can generally receive red cells from any Rh-negative donor: O−, A−, B−, and AB−.
What AB− means
AB indicates both A and B antigens are present on red cells with no ABO antibodies typically in plasma. The minus sign indicates the RhD antigen is absent.
AB− recipients can generally accept red cells from any Rh-negative type because they lack anti-A and anti-B antibodies. They are generally matched with Rh-negative red cells.
AB negative is one of the rarest common blood types in many populations. AB− plasma is especially valuable because it is compatible with all ABO recipients.
| Property | Value |
|---|---|
| ABO group | AB |
| Rh (D) status | Negative (RhD antigen absent) |
| Red cell antigens | A, B |
| Plasma antibodies (typical) | None (ABO) |
Compatibility summary
General red cell and plasma compatibility for AB− under the simplified ABO/Rh model. Real transfusions also depend on antibody screening and crossmatching.
| Product | Can give to | Can receive from |
|---|---|---|
| Red blood cells | AB−, AB+ | O−, A−, B−, AB− |
| Plasma (ABO only) | A, B, AB, O | AB |
See the full compatibility chart for all eight types.
Inheritance context
Type AB has only the AB genotype; one parent contributed A and the other B. Rh-negative requires dd, so each parent contributed a d allele.
An AB− child could have two Rh-positive parents if both are Dd, or one or both Rh-negative parents.
An AB child cannot have a type O parent under the standard model.
Work through specific parent combinations with the baby blood type calculator, or find which parent types could produce a AB− child with the parent calculator.
Limitations
- Blood type can only be confirmed by laboratory testing. Family history, calculators, and self-report are not substitutes.
- Compatibility rules on this page are general educational summaries. Real transfusion decisions also depend on antibody screening, crossmatching, product type, and clinical judgment.
- Rare variants such as the Bombay phenotype, cis-AB, and weak or partial D expression can produce results that differ from the simplified ABO/Rh model.