The proper name for a unit of whole blood-derived red blood cells from which the vast majority of the white blood cells have been removed (see the entry on Leukoreduction for some reasons why we want to get rid of white blood cells). This product is commonly abbreviated as “LRBCs.” By definition, LRBCs must be made using a method that retains at least 85% of the red blood cells present in the original unit, and, in the United States, must contain less than 5.0 x 10⁶ residual white blood cells (that number is 1.0 x 10⁶ in Europe).