Cell lines indicate the “pedigree” of the cells producing the antibody used in a monoclonal reagent. Each cell line actually has its own specificity and you will occasionally see differences between the reactions from different cell lines for the same antibody specificity. AABB Standards requires that IRLs have two examples of some antisera. The laboratory staff needs to determine the cell lines used in the reagents they purchase to make sure they have two examples because it is not unusual for multiple manufacturers to utilize the same cell line. Quotient primarily utilizes cell lines that have not been previously distributed in the United States and can aid IRLs in meeting this requirement.