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. The ABO antibodies (anti-A and anti-B) are naturally occurring - present from infancy against whichever A or B antigen you lack. The Rh anti-D antibody is different: Rh-negative people do not carry it from birth and only form it after exposure to Rh-positive blood through transfusion or pregnancy (sensitisation), which is why anti-D immunoglobulin is given to prevent it. 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 +Updated 2026-04-27