Less common - 6.3% of US donors
A-negative blood carries the A antigen but lacks the Rh-D antigen. This makes A-negative donors especially valuable: they can donate to A-positive, A-negative, AB-positive, and AB-negative recipients - covering all four A-type and AB-type individuals. Like O-negative, A-negative blood is safe for Rh-negative recipients, which widens its usefulness considerably.
Antigens present
A antigen only (no B, no Rh-D)
Antibodies produced
Anti-B, Anti-D
Antigens are proteins on the surface of red blood cells. Antibodies are produced by the immune system against antigens it does not carry. When incompatible blood is transfused, antibodies bind to foreign antigens and trigger a haemolytic reaction.
Select your blood type:
Can donate red cells to:
4 compatible types
Can receive red cells from:
2 compatible types
| Population | Frequency |
|---|---|
| US blood donors (Red Cross estimate) | 6.3% |
| Global population (estimate) | 6.1% |
A-negative is found in approximately 6.3% of US donors and 6.1% of the global population. It is relatively uncommon, which makes each A-negative donor valuable to the blood supply. A-negative is more common in Europe, particularly in Nordic and Celtic populations, and less common in East Asian and African populations.
A-negative individuals share the same ABO-related epidemiological associations as A-positive (modest A-type epidemiological patterns). The Rh-negative status means they lack the Rh-D antigen, which is generally clinically neutral in everyday life. There are no known health disadvantages to being Rh-negative. A-negative people can donate whole blood every 56 days. Platelets from A-negative donors are particularly useful in paediatric and cancer care.
Note: Associations between blood type and disease risk are from observational studies and are not deterministic. They do not change your clinical management. Cite any specific associations with your clinician.
A-negative mothers are Rh-negative. If you are A-negative and the father of your baby is Rh-positive, there is a chance your baby will be Rh-positive. This creates the risk of Rh sensitisation - where your immune system produces anti-D antibodies that could, in a future pregnancy, cross the placenta and attack fetal red cells. Anti-D immunoglobulin (RhoGAM) is routinely offered to Rh-negative mothers at around 28 weeks and within 72 hours of delivery. This prophylaxis is highly effective. Ensure your obstetrician records your blood type at your first antenatal appointment.
Full Rh factor pregnancy guide +A-negative organ donors can give to A+, A-, AB+, and AB- recipients. As an A-negative recipient, you can only receive organs from A-negative or O-negative donors - a smaller pool that may mean longer waiting times on transplant lists. Paired kidney exchange programs can help bridge ABO and Rh incompatibilities in living-donor situations. HLA tissue matching and crossmatch testing are required in addition to ABO compatibility.
ABO compatibility for organ transplant follows the same rules as transfusion - A- can donate organs to: A+, A-, AB+, AB-. However, HLA tissue matching and crossmatch testing are also required, and sensitisation from prior transfusions or pregnancies can restrict compatibility further.
Full organ transplant guide +A-type plasma (both A+ and A-) contains anti-B antibodies and can be given to A or O recipients. The Rh factor is not relevant for plasma compatibility. If you are A-negative, consider whole blood or red cell donation as your primary contribution, as your red cells are more uniquely valuable than your plasma.
Note: Plasma compatibility rules are the inverse of red-cell rules because plasma carries antibodies, not antigens. AB plasma is the universal plasma donor.
Plasma compatibility chart +