In addition to the A and B antigens, there is a protein called the Rh factor, which can be either present (+) or absent (–), creating the 8 most common blood types (A+, A-, B+, B-, O+, O-, AB+, AB-). There are very specific ways in which blood types must be matched for a safe transfusion.
There are eight blood types included in the ABO and Rh blood group systems: A positive (A+), A negative (A-), B positive (B+), B negative (B-), AB positive (AB+), AB negative (AB-), O positive (O+), O negative (O-).
About 9% of the population has B+ blood. Your blood can be transfused to both B+ and AB+ patients. In trauma situations and surgeries, it is important to have your blood type readily available. Your platelets are the most powerful part of your B+ blood.