Clarification on Item List vs. Quantity List in Traceability Events

[ashleythedeveloper]

Hi UNTP Community,

I’m seeking some guidance on the proper implementation of digital traceability events in relation to the use of item lists and quantity lists.

Questions:

1. Serialised Items:
   Is it correct to assume that when an item is uniquely identified (e.g., by a serial number), we should represent it using the item list exclusively, leaving the quantity list empty or omitted?

2. Product Identifier with Quantity:
   How should we handle cases where a product identifier is associated with the product and its quantity, but the product isn’t uniquely serialised? Does this scenario classify as a serialised item, or should it be treated as a measured quantity? In other words, which list (item or quantity) is the appropriate place to record such a product?

3. Product Aggregation:
   In cases where identifiers represent aggregated units, is it acceptable—or even preferred—to use the item list instead of the quantity list?

For example, I produce copper cathodes that have a product ID "123", I then aggregate 10 of these products into a box and this box of 10 copper cathodes has an ID of "456, I then aggregate the 10 boxes of copper cathodes onto a pallet which is identifiable by the ID "789".

If I sold the pallet to "acme corp", would I represent this within a transaction event as:

      "epcList": [
        {
          "type": [
            "Item",
            "Entity"
          ],
          "id": "https://id.example.com/product/789",
          "name": "Copper Cathodes",
          "registeredId": "789",
          "idScheme": {
            "type": [
              "IdentifierScheme"
            ],
            "id": "https://id.example.com/product/",
            "name": "Product"
          }
        },

or

      "quantityList": [
        {
          "product": {
            "type": [
              "Entity"
            ],
            "id": "https://id.example.com/product/123",
            "name": "Lithium hydroxide",
            "registeredId": "123",
            "idScheme": {
              "type": [
                "IdentifierScheme"
              ],
              "id": "https://id.example.com/product/abc",
              "name": "Product"
            }
          },
          "quantity": 100,
          "uom": "EA"
        },

or both?

Thank you in advance.