Basic UDI-DI: What It Groups, and Why the Grouping Decides Your Costs
Updated: Aug 30
Three identifiers appear in EUDAMED and manufacturers confuse them routinely. The Basic UDI-DI groups devices. The UDI-DI identifies a specific version of a device. The EUDAMED DI exists because legacy devices have neither.
What the Basic UDI-DI does
The Basic UDI-DI is the primary identifier of a group of devices sharing the same intended purpose, risk class and essential design and manufacturing characteristics. It is defined in Annex VI, Part C of Regulation (EU) 2017/745 and in the corresponding annex of Regulation (EU) 2017/746.
It does not appear on the label. It does not appear on the packaging. It lives in the technical documentation, in the declaration of conformity, in certificates issued by a notified body, and in the database. Its function is to be the key that ties those documents to the device group they describe.
The Basic UDI-DI is assigned by an issuing entity designated by the Commission, and once assigned it is not reused for a different device group.
Basic UDI-DI and UDI-DI are not the same thing
The UDI-DI identifies a particular version of a device: a size, a configuration, a packaging level. It appears on the label as part of the UDI carrier, and it is what a hospital scans at the point of use.
One Basic UDI-DI can carry many UDI-DIs. A device sold in six sizes is one Basic UDI-DI and six UDI-DIs, not six devices. A device offered sterile and non-sterile is a harder question, because sterility may affect risk class and therefore the grouping itself.
The relationship runs one way. Every UDI-DI belongs to exactly one Basic UDI-DI; a Basic UDI-DI belongs to no higher identifier.
Legacy devices have no Basic UDI-DI
Devices placed on the market under the previous Directives were never assigned a Basic UDI-DI, because the concept did not exist under that framework. Registering them in EUDAMED therefore uses a EUDAMED DI, assigned specifically for that purpose.
Regulation (EU) 2024/1860 sets the rules for legacy device registration, and the Commission points to MDCG 2021-25 for MDR legacy devices and MDCG 2022-8 for IVDR legacy devices.
Entering a legacy device as though it had a Basic UDI-DI produces a record of the wrong type. It is one of the more common errors in legacy registration and one of the more tedious to unwind, because the correction touches every record linked to it.
How to decide a Basic UDI-DI grouping
The grouping is driven by three things: intended purpose, risk class, and essential design and manufacturing characteristics. All three must be shared for devices to sit under one Basic UDI-DI.
It is not driven by catalogue structure. A catalogue that has grown organically over fifteen years reflects commercial history rather than regulatory logic, and using it as the grouping basis reliably produces either too many groups or the wrong ones.
Where a device family includes variants that differ in risk class — a sterile version alongside a non-sterile one, for instance — those variants cannot share a Basic UDI-DI, because risk class is part of the grouping criterion.
Why Basic UDI-DI grouping affects what you pay
Most authorised representatives price representation by Basic UDI-DI rather than by catalogue reference. That makes the grouping decision commercial as well as regulatory.
Group too narrowly and you multiply your Basic UDI-DIs, and with them your documentation sets, your certificate references and your annual representation fee. Group too broadly and the grouping stops reflecting how the devices actually reach the market, which is a regulatory finding rather than a saving.
When comparing quotes from representatives, ask each of them how many Basic UDI-DIs they arrive at for the same portfolio. The answers will differ, and the difference tells you something about how carefully each has read your device list.
Sources
Regulation (EU) 2017/745, Article 27 and Annex VI, Part C — UDI system
Regulation (EU) 2017/746, Article 24 and Annex VI, Part C
Regulation (EU) 2024/1860 — gradual roll-out of EUDAMED and registration of legacy devices
MDCG 2021-25 — application of MDR requirements to legacy devices
MDCG 2022-8 — application of IVDR requirements to legacy devices
European Commission — Management of legacy devices in EUDAMED, EUDAMED DI format
Who wrote this
Medex is a medical device manufacturer established in Ankara and a registered authorised representative in EUDAMED under SRN TR-AR-000057550, with Basic UDI-DI and UDI-DI records filed for our own devices. We are not a law firm and do not provide legal advice.
Medex assigns and files these identifiers as part of EUDAMED registration, and because grouping drives cost, our annual representation fee is published per class rather than per record.
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