What fundamental requirement distinguishes modern supply chain serialization from earlier tracking methods like batch or case tracking?

Serialization requires that the identifier be globally unique across the entire product lifecycle.

The defining characteristic that elevates modern serialization above antecedent tracking methods, such as batch tracking or the early use of barcodes on shipping cases, is the mandate for a globally unique identifier for every single saleable unit. While older systems focused on identifying groups of items, serialization demands granularity down to the individual item, and this item's identifier must remain consistent and recognizable across every stage it passes through—from manufacturing through wholesale distribution to the final point of dispensing—throughout its entire existence in the supply chain. This global uniqueness is what enables precise tracing and verification necessary for high-stakes goods like pharmaceuticals, making the tracking specific to the item, not just the shipment or batch it belongs to.