About blood types

Often abbreviated ABO, blood types are inherited and fall into four groups or types: O, A, B, AB. Each blood type also is identified as either Rh positive or negative (the Rh factor being an inherited blood group on red blood cells). Approximately 85% of the U.S. population is Rh-positive (i.e., O+, A+, B+, AB+). Those who do not have the Rh factor are Rh-negative (O-, A-, B-, AB-) and are quite rare.

 O+  38%  
 O-  7%  Universal red cell donors
 A+  34%  
 A-  6%  
 B+  9%  
 B- 2%
 AB+ 3%
 Universal plasma donors and red
 cell recipients
 AB-  1%  Universal plasma donors

Learn more
About Blood Components
Whose Type Can You Match?
Right Type for Your Type