Apr 24, 2018


  • The Basic UDI-DI is the key identifier of a device in Eudamed, on certificates and on the Declaration of Conformity.
  • Multiple UDI-DIs can be linked to a single Basic UDI-DI, while a UDI-DI must be linked to only one Basic UDI-DI.
  • The UDI-DI must unambiguously identify a device in the distribution chain; any change that may confuse identification should result in a new UDI-DI.
  • Manufacturers can now identify the data elements and formats for developing their databases in preparation of the introduction of UDI in Europe.

What is UDI?

In short the Unique Device Identification (UDI) consists of a code on the label of a device. The first part of this code is unique and linked to all devices of that specific type; the second part of the code is linked to homogenous production of devices (e.g. batch, serial number, etc.).  FDA is already rolling out UDI, while the EU is implementing this system and most other markets are also working on introducing UDI. So far it looks as if all these markets will accept the same codes on the label. However, each code is linked to information in a database, and on national level these databases are likely to have differences in fields, field formats and UDI hierarchy and relations between devices. It is likely these differences will not be solved within the next five years.

At its March 2018 meeting the European Medical Devices Coordination Group (MDCG) endorsed guidance documents covering UDI and related issues.

The endorsed guidances pertain to UD-DI, the European UDI database and UDI architecture in Eudamed.

The guidance on the database provides information on the data elements and their format, while the architecture guidance places these elements in context.

It is not clear why the MDCG document is referred to as a “draft” because no further formalization of the document is foreseen now that the MDCG has endorsed it. It must also be understood that this is only a guidance document, providing a common understanding of the requirements. The final interpretation of the Regulations leading to legally binding conclusions must be left to the Court of Justice of the European Union.

Basic UDI-DI

In Annex VI, Part C of Medical Devices Regulation 2017/745, the Basic UDI-DI is defined as: “… the primary identifier of a device model. It is the DI assigned at the level of the device unit of use. It is the main key for records in the UDI database and is referenced in relevant certificates and EU declarations of conformity.” The guidance document specifies this further: “devices with same intended purpose, risk class and essential design and manufacturing characteristics.”

The Basic UDI-DI is therefore the key identifier of a device, or a group of devices with variations that do not have a major impact on their function. For example: Wires that only vary in length may have the same Basic UDI-DI, but if the difference in length leads to different intended purposes, they should have different Basic UDI-DIs.

In order to identify the device unambiguously on a certificate, declaration of conformity and other relevant documents the Basic UDI-DI can be used to refer to information in the UDI module of Eudamed. In this way the Basic UDI-DI represents the information in Eudamed related to the device, summarizing details only accessible for those with sufficient authorization in Eudamed. All devices covered by that Basic UDI-DI should be covered by that single certificate. However, the Basic UDI-DI is not intended to replace information like the trade name, product code, catalogue number and other ways to identify the device on declarations of conformity. This is done because a single Basic UDI-DI may refer to several UDI-DIs with different specifications. Especially when it comes to vigilance and traceability, this level of detail is required.


According to Annex VI, Part C, the UDI-DI is “… a unique numeric or alphanumeric code specific to a model of device that is also used as the ‘access key’ to information stored in a UDI database.” Obviously, a UDI-DI must be associated with exactly one Basic UDI-DI. The UDI-DI is needed to identify a specific device within the supply chain. If a change in the design could lead to misidentification of the device, a new UDI-DI should be created. The guidance document specifies the following conditions for creating a new UDI-DI:

  • A change in name or trade name;
  • A change of device version or model;
  • Labelled as single use device where this was previously not the case;
  • Package sterile where this was previously not the case;
  • The need for sterilizing before use, where this was not the case previously;
  • A change of quantity of devices in a package;
  • Added or changed critical warnings or (contra-)-indications;
  • A change regarding the presence of CMR/Endocrine disruptors;
  • Changes in color;
  • Languages added or removed.

However, this list should not be considered exhaustive. Any other change should be evaluated for the need for a new UDI-DI.


The UDI-PI is used to identify specific production series of a device (batch, serial number etc.). In case of minor non-relevant changes the UDI-PI will can also be used for identification of specific generations of the device. However, the UDI-PI cannot be used to replace different UDI-DIs.

Basic UDI-DI in relation to UDI-DI

The data elements for the Basic UDI-DI are obvious:

  • Basic UDI-DI value;
  • Single Registration Number of the manufacturer;
  • Name and address of the manufacturer;
  • Name and address and Single Registration Number of the authorized representative;
  • Risk class and additional characteristics necessary to identify specific conformity assessment features (implantable, measuring function, etc.);
  • Medical device nomenclature code;
  • Name or model identifying the Basic UDI-DI group in the technical documentation  and/or certificate and declaration of conformity.

The data elements of the components specific to various models identified by the UDI-DIs do not only contain the obvious characteristics (quantity, clinical size, etc.). These elements would also appear to be typical for those required for the Basic UDI-DI, because these elements refer to design, intended use and performance. These are typical elements that would be related to the “intended purpose, risk class and essential design and manufacturing characteristics.” The most obvious of these are:

  • Type of UDI-PI;
  • Labelled as single use device;
  • Sterile;
  • Need for sterilization;
  • Containing latex;
  • CMR/Endocrine disruptor;
  • Medical device nomenclature code;
  • Reprocessed single use (reprocessing a single use device places manufacturers’ responsibility on the re-processor. This would also imply a new Basic UDI-DI);
  • Annex XVI;
  • The relevant details in the case of devices designed and manufactured by another legal or natural person.

For other data elements it is unclear why they should be related to the UDI-DI and the Basic UDI-DI:

  • References, article number etc.;
  • Quantity per device;
  • Clinical size;
  • Storage/handling conditions;
  • Name/Trade name;
  • Additional trade name (because a device may be sold under different brands – see article 16.1a MDR);
  • Additional product description;
  • URL for additional information;
  • Critical warnings (if the types of this device are used in a different context, certain warnings may vary);
  • Status (e.g. no longer made available).

Data formats

The document about the UDI Database, definitions/descriptions and formats of the UDI core elements describes the data formats of the elements used in the UDI database. These list typical data characteristics like Number (integer), String (boxes to check), drop down list (“select one”), free text, etc. This table does not provide the size of these fields or the exact boxes to check. It is expected that later in the 2018 these details will also be provided. Manufacturers can already start developing their databases using this table. It is expected that the publication of the functional specifications – probably in June of 2018 – will provide most of the additional information.

Related European medical device regulatory resources from Emergo:



  • Ronald Boumans