Six common mistakes on medical device UDI labels

A unique device identifier (UDI) for medical devices has two parts. The device identifier (UDI-DI) identifies the model and its packaging and does not change; the production identifier (UDI-PI) carries the information that changes with every production run, such as the lot, serial number, manufacturing date or expiry date. In the GS1 system the UDI-DI is a GTIN (01); the UDI-PI uses (10) lot, (21) serial number, (11) production date and (17) expiry date.

In the EU this structure is set out in the MDR (2017/745); the US FDA's UDI rule follows the same logic. The mistakes below are the ones we see most often at the label design and master data stage.

This article summarizes a software team's perspective; it is not regulatory advice. For binding requirements, refer to the applicable regulation and your notified body.

1. The same UDI-DI on every packaging level

The single device, the inner box and the case are different packaging levels, and each carries its own UDI-DI. Printing the same GTIN on the single device and on a box of ten leaves it unclear how many devices one scan represents. Shipping containers used for logistics are exempt; they use an SSCC.

What helps: keep the device and each packaging level as separate master data records, each with its quantity and the GTIN of the level below.

2. No new UDI-DI after a change

The MDR requires a new UDI-DI whenever a change could lead to misidentification of the device. The list includes the name or trade name, the model or version, single-use labelling, sterile packaging, the need for sterilization before use, the quantity in a package, and critical warnings such as containing latex or DEHP. Raising the pack quantity from 10 to 12 and keeping the same GTIN is a common mistake.

What helps: add "does this affect the UDI-DI?" as a mandatory step in the product change process.

3. Confusing Basic UDI-DI with UDI-DI

The Basic UDI-DI identifies a group of devices with the same intended purpose, risk class and essential design. It appears in EUDAMED, in the declaration of conformity and in certificates, but not on the label; the label carries the UDI-DI. Master data that keeps both in the same field produces inconsistencies between registration and label.

4. A production identifier that doesn't match how the device is controlled

The UDI-PI reflects how the manufacturer controls the device: (10) for lot-controlled devices, (21) for serialized ones, and (17) whenever there is an expiry date. An expiry date printed on the label but missing from the barcode, or only a lot encoded for a serialized device, leaves the UDI incomplete.

5. Human-readable text that differs from the barcode

The UDI appears on the label both in machine-readable form (the barcode) and in human-readable form (HRI). When the two are fed from separate template fields, one gets updated and the other is forgotten. The HRI should be generated from the barcode content; in GS1 the fields are written with identifiers in parentheses: (01)…(17)…(10)….

6. Print quality that is never measured

Small devices have little label space, and the symbol gets shrunk. A barcode that scans is not enough; quality grades are measured with ISO/IEC 15415 for 2D symbols and ISO/IEC 15416 for linear barcodes. Periodic measurement with a verifier reduces the risk of unreadable labels in the field.

Quick check

You can split the barcode content of a label into its fields with the GS1 barcode decoder and check that the device identifier and a production identifier are present. GTIN check digits can be verified in bulk with the check digit calculator. If you want to look at labelling and UDI database integration together, get in touch.