ISBT 128 unit identification numbers are unique worldwide. Unique numbers eliminate the need to reassign local numbers when more than one blood supplier is utilized. ISBT 128 incorporates the year of collection into the unit identification number. This is important because many hospital transfusion service computer systems will not allow duplicate unit identification numbers. Assigning a local number by definition leads to further opportunity to lose track of the final disposition of a unit.
Unique numbers allow for centralized testing.
ISBT 128 allows for more characters in a unit identification number, which in turn allows the drawing center location to be encoded as a part of the unit number. Codabar unit identification numbers, on the other hand, are short and duplicated frequently across the country. This lack of uniqueness leads to duplicate numbers when a laboratory does testing for other facilities. In order to accommodate this centralized testing, at least one laboratory is using Code 128 on sample tubes and Codabar on blood labels. Thus, when you scan the identification number on the unit of blood, it has two fewer digits than its corresponding eye readable number.