The aim of this system, established under Article 27 of the MDR and related delegated acts, is to streamline the identification of similar products by assigning a single identifier, known as the Master UDI-DI, rather than generating thousands of individual device identifiers.
Who is affected?
The new obligations apply to the following categories of medical devices:
- Contact lenses (Class IIa/IIb),
- Spectacle frames, spectacle lenses, and ready-to-wear reading spectacles (Class I).
For contact lenses, the assignment of a Master UDI-DI becomes mandatory as of 9 November 2026. For spectacle frames, lenses, and reading glasses, the implementation deadline is set for September 2028.
What needs to be done?
The rollout of the Master UDI-DI solution consists of three key phases:
- Identifier assignment – Manufacturers must assign a Master UDI-DI based on grouping devices with similar design parameters, following the rules established by designated UDI issuing entities.
- Labelling – Once the Master UDI-DI is assigned, it must be placed on the device label and all higher levels of packaging, in accordance with Article 27(4) of the MDR.
- Registration in EUDAMED – The Master UDI-DI must be registered in the UDI/Device registration module of EUDAMED. This obligation is closely linked to the timeline of UDI-DI assignment.
Importantly, the MDCG strongly encourages voluntary early assignment of Master UDI-DIs before the official deadlines. Doing so allows manufacturers to become familiar with the system and leverage EUDAMED’s functionalities in advance, avoiding last-minute implementation bottlenecks.
Integration with Post-Market Surveillance
Once the Vigilance and PMS modules of EUDAMED become mandatory (currently expected in Q3 2026), any assigned Master UDI-DI will also need to be used in incident and field safety corrective action reporting. This reflects the growing integration of UDI data into broader post-market safety and reporting systems under the MDR.
Next steps
The MDCG has announced plans to publish additional guidance documents, including an updated MDCG 2024-14 for contact lenses and a new MDCG 2025-XX for Class I optical devices such as frames and reading glasses.