Common - 8.5% of US donors
B-positive blood carries the B antigen and the Rh-D antigen on red cells. It is the third most common type in the US at 8.5% of donors. B-positive people produce anti-A antibodies and can donate red cells to B-positive and AB-positive recipients. While less common than A and O types in the US, B-positive is significantly more prevalent in South Asian and East Asian populations.
Antigens present
B antigen, Rh-D antigen
Antibodies produced
Anti-A
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:
2 compatible types
Can receive red cells from:
4 compatible types
| Population | Frequency |
|---|---|
| US blood donors (Red Cross estimate) | 8.5% |
| Global population (estimate) | 22% |
B-positive accounts for about 8.5% of US donors but approximately 22% of the global population. This disparity reflects geographic genetics: B blood group is significantly more prevalent in South Asia (India, Pakistan, Bangladesh), Central Asia, and parts of East Asia than in Western Europe or the Americas. In the US, B-positive is the third most common type after O-positive and A-positive.
B-type individuals share some ABO-related epidemiological patterns. Some studies suggest slightly elevated risk of pancreatic cancer and venous thromboembolism in non-O types including B, though these are statistical population associations rather than individual predictions. B-positive individuals are eligible for all standard donation types: whole blood, Power Red, platelets, and plasma. Platelet donation is particularly valuable as B-positive platelets are in consistent demand.
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.
B-positive mothers are Rh-positive, so Rh incompatibility is not a pregnancy concern. ABO incompatibility between an O-type mother and a B-type baby can occasionally cause mild newborn jaundice, but this is usually not serious and does not require prenatal intervention. If you are B-positive and pregnant, neither your ABO type nor your Rh-positive status creates specific blood-type related pregnancy risk.
Full Rh factor pregnancy guide +B-positive organ donors can give to B-positive and AB-positive recipients. As a B-positive recipient, you can receive organs from B+, B-, O+, or O- donors. This gives B-positive patients a reasonable donor pool size. For kidney transplant in particular, living donors are preferred when compatible - the National Kidney Foundation recommends discussing living donation with family members who may be B-type or O-type.
ABO compatibility for organ transplant follows the same rules as transfusion - B+ can donate organs to: B+, 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 +B-type plasma (both B+ and B-) contains anti-A antibodies. B plasma can be given to B or O recipients. For plasma donation, AB-type is universally preferred. If you are B-positive, consider whole blood or platelet donation as your primary contribution.
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 +