EU MDR FAQ UDI-DI and Basic UDI-DI

The manufacturer decides the Basic UDI-DI grouping from its technical knowledge and the issuing entity's rules. Group only devices that share the same intended purpose, risk class, and essential design and manufacturing characteristics. The Basic UDI-DI is the main database and documentation key; it appears in the EU declaration of conformity and, where applicable, product certificates, technical documentation, the summary of safety and clinical performance (SSCP), and the periodic safety update report (PSUR). It is not placed on the device label.

Assign a UDI-DI to the device model and a separate UDI-DI to each higher packaging level, excluding shipping containers. The UDI-DI is specific to a manufacturer and device. It combines with the production identifier, or UDI-PI, to form the UDI conveyed by the UDI carrier. A Basic UDI-DI may link to one or more UDI-DIs, but each device UDI-DI links to one Basic UDI-DI in EUDAMED.

The UDI carrier is the AIDC and HRI representation of the UDI. As a general rule, it is placed on the label or device itself and on higher packaging levels. Annex VI contains exceptions for space constraints, certain individually packaged class I and IIa single-use devices, retail point-of-sale packaging, direct marking, and systems or procedure packs. The UDI requirement does not replace the rest of the MDR labelling requirements.

Manufacturers must submit UDI/device information in EUDAMED for devices subject to the registration requirements. The UDI/Devices module has been mandatory since 28 May 2026. Before placing a device other than a custom-made device on the market, the manufacturer must enter or verify the applicable Annex VI device information and keep it updated. A UDI-DI record does not prove that the device conforms to the MDR.

A new UDI-DI is required when a change could lead to device misidentification or ambiguity in traceability. MDR Annex VI makes a new UDI-DI mandatory for changes to the name or trade name, device version or model, single-use status, packaged-sterile status, need for sterilisation before use, quantity in a package, or critical warnings or contraindications such as latex or DEHP.

The list does not replace the general misidentification and traceability test. MDCG 2022-7 applies that test to package quantity and substance-based devices. Software has additional Annex VI rules: a modification that changes original performance, safety or intended use, or interpretation of data requires a new UDI-DI, while minor revisions generally require a new UDI-PI.

MDR Article 27(7) requires the manufacturer to keep an up-to-date list of all assigned UDIs in the technical documentation. The supporting record should also link each identifier to the product facts that justify it: Basic UDI-DI grouping rationale, issuing entity rule, device and packaging level, label or carrier evidence, EUDAMED data, and the change assessment explaining why the identifier stayed the same or changed.

For reprocessing and relabelling situations, keep traceability back to the original device identifier where the guidance or MDR rule calls for it. MDCG 2022-7 says a reprocessor who becomes the manufacturer should keep the original product UDI in technical documentation and the QMS, and MDR Annex VI requires manufacturers that relabel or repackage devices with their own label to retain the original manufacturer's UDI.