EU Medical Devices: Understanding the basics of the UDI system

Last updated: 23 August 2022

This post is an attempt to facilitate understanding of the basics of the UDI system, an EU identification system for medical devices introduced in the Medical Devices (EU) Regulation (EU) 2017/745 (MDR) and the In Vitro Diagnostic Medical Devices Regulation (EU) 2017/746 (IVDR). As a minimum, it is important to understand the following terms:

  1. Basic UDI
  2. Unique Device Identifier (UDI) – It consists of the UDI-DI and the UDI-PI
  3. Unique Device Identification (UDI) system
  4. UDI carrier

Unusually, it seems that the acronym ‘UDI’ is used to mean both, Unique Device Identifier and Unique Device Identification (when referring to the UDI system).

1. What is the Basic UDI?

The Basic UDI is defined in Annex VI Part C of the MDR and the IVDR, but the definition below might be easier to follow:

  • The Basic UDI is the main access key for device-related information in the EUDAMED database.
  • Any Basic UDI-DI shall identify the devices (group) covered by that Basic UDI-DI in a unique manner.
  • It is intended to identify and connect devices with:
    • The same intended purpose
    • The same risk class
    • The same essential design
    • The same manufacturing characteristics
What is an example of a Basic UDI?

One example is the GMN (Global Model Number). It is a GS1 Key used to identify a product model or product family. The Global Model Number enables companies to uniquely identify the product model through the entire life cycle of the product i.e. design – production – procurement – use – maintenance – disposal.

Where can you expect to see the Basic UDI?

The Basic UDI is referenced in relevant documentation for example:

  • Certificates including certificate of free sale
  • EU Declaration of Conformity (DoC)
  • Technical Documentation (TD)
  • Summary of Safety and Clinical Performance (SSCP)

It is important to note that the Basic UDI is independent/separate from the packaging/labelling of a device and it does NOT appear on any trade item.

2. What is the Unique Device Identifier (UDI)? 
  • The Unique Device Identifier (UDI) is a series of numeric or alphanumeric characters that is created through a globally accepted device identification and coding standard.
  • It allows the unambiguous identification of a specific device on the market. (MDR and IVDR Annex VI Part C)
  • The UDI will be a barcode, a QR code or any other machine-readable code (more information in section 4. UDI carrier)
What is the Unique Device Identifier comprised of?

The UDI is comprised of the following two parts

  • the UDI Device Identifier (UDI-DI)
  • the UDI Production Identifier (UDI-PI).
i. What is the UDI-DI?

This is the static part of the UDI.

  • The Device Identifier of the UDI is a unique numeric or alphanumeric code specific to a version or model of a medical device.
  • This mandatory, fixed portion/static part of a UDI identifies a manufacturer’s specific product and package configuration
  • It is specific to a manufacturer and a device
  • The UDI-DI shall be unique at each level of device packaging. (MDR Annex VI Part C)
What are some examples of UDI-DI?

Examples include the following:

  • GS1 GTIN (Global Trade Item Number),
  • HIBC-UPN (Universal Product Number),
  • ICCBBA ISBT 128-PPIC (Processor Product Identification Code).
ii. What is the UDI-PI?

This is the dynamic part of the UDI. It is a variable/dynamic code related to production data of the device

The Production Identifier of the UDI is a numeric or alphanumeric code that identifies the unit of device production when one or more Production Identifier pieces of information (see below) are included on the package label of a device.

What are some examples of UDI-PI?

Examples include the following:

  • The Device Batch/Lot No – e.g.
  • Manufacture date – e.g. 250717
  • The Expiration date of a specific device e.g. 141120
  • The Serial number of a specific device – e.g. 12345XYZ
  • Software as a Medical Device (SaMD) version
3. What is the UDI system?

The MDR (Article 27) and the IVDR (Article 24) introduce an EU identification system for medical devices based on a Unique Device Identifier (UDI) called the Unique Device Identification system (UDI system).

What shall the UDI system consist of?

According to the MDR Article 27 and the IVDR Article 24, the UDI system shall consist of the following:

  1. Production of a UDI that consists of the following:
    -A UDI-DI
    -A UDI-PI
  2. Placing the UDI on the label of the device or on its packaging.
  3. Storage of the UDI (by electronic means) by economic operators, health institution and health care professionals in accordance with the conditions laid down in the MDR Article 27 and IVDR Article 24
  4. Establishment of an electronic system for Unique Device Identification (UDI database). This refers to the new EUDAMED database (currently under development) which will include a UDI database.
What is the function of the UDI system?

To allow the identification of and facilitate the traceability of devices (MDR Article 27 and IVDR Article 24).

What are some of the benefits of having a UDI system?

According to the MDR (Preamble 41) and IVDR (Preamble 38), some of the benefits of having a UDI system are:

  • The traceability of devices by means of a Unique Device Identification system (UDI system) based on international guidance should significantly enhance the effectiveness of the post-market safety-related activities for devices, which is owing to improved incident reporting, targeted field safety corrective actions (FSCAs) and better monitoring by competent authorities
  • It should also help to reduce medical errors and to fight against falsified devices
  • It should also improve purchasing and waste disposal policies and stock-management by health institutions and other economic operators and, where possible, be compatible with other authentication systems already in place in those settings.
  • Economic operators shall be able to identify any health institution or healthcare professional to which they have directly supplied a device (MDR Article 25 and IVDR Article 22)
To which medical devices will the UDI system apply?

The new system will be applied to all medical devices except the following:

  • custom-made devices (MDR preamble 42 and Article 27)
  • investigational devices (MDR Article 27)
  • performance study devices (IVDR preamble 38 and Article 24)
4. What is a UDI carrier? (MDR and IVDR Annex VI Part C)

The UDI carrier is the means of conveying the UDI by using AIDC (Automatic Identification and Data Capture) and, if applicable, its HRI (Human Readable Interpretation).

What does this mean in simple terms?

In simple terms, this means that the UDI (that is the DI + PI parts), in order to be put on the device or packaging label or on the device itself must be available in the following two representations:

  • Easily readable plain-text or HRI
  • Machine-readable form that uses automatic identification and data capture (AIDC) technology. AIDC technologies include bar codes (e.g. linear bar codes, “2DMartix bar codes), smart cards, biometrics and RFID.

More about AIDC and RFID:

AIDC is any technology that conveys the UDI or the device identifier of a device in a form that can be entered into an electronic patient record or other computer system via an automated process.

RFID is a technology that uses communication through the use of radio waves to exchange data between a reader and an electronic tag attached to an object, for the purpose of identification.

Where can you expect to see the UDI carrier?

The UDI carrier will appear on the device or packaging label or on the device itself.

Where can you see a sample label that will enable you to understand all of this jargon?

If you want to see how the UDI (the DI + PI parts), the AIDC e.g. linear bar codes or 2D bar codes and HRI appear on a label, please see this link here. Please note that the samples are based US FDA legislation and NOT EU legislation but you will at least get an idea of how all of these elements appear visually.

In case you are interested in formal definitions of HRI, AIDC and UDI carriers, you will find them in both, the MDR and the IVDR Annex VI Part C.

Who is responsible for placing the UDI carrier (AIDC and HRI representation of the UDI) on the device itself, on the label and on the package of a device?
  • The manufacturer is responsible for complying with all UDI related requirements.
  • This includes the assignment of the UDI (and Basic UDI-DI), the UDI (and Basic UDI-DI) registration in the EUDAMED database and the placement of the UDI carrier on the label of the device or on its packaging or, in case of reusable devices, on the device itself (direct marking).
Are there more specific rules governing the UDI?

Yes, within the MDR and IVDR there is specific guidance available on e.g.:

  • Should a UDI shall be assigned to the device itself or its packaging?
  • Should higher levels of packaging shall have their own UDI
  • Is there a requirement for the UDI-DI to be unique at each level of device packaging.
  • Is a new UDI required when there is a change to the device e.g. name or trade name change, device version or model etc.?

The above is by no means an exhaustive list.

You can find this guidance in MDR and IVDR Annex VI Part C in the following sections:

  • Section 3 The UDI
  • Section 4 UDI carrier
  • Section 6 Rules for specific device types
Is it a requirement that both representations of the UDI carrier i.e. the AIDC part and the HRI part should always appear on a label?

If there are significant constraints limiting the use of both AIDC and HRI on a label, only the AIDC format shall be required to appear on the label. For devices intended to be used outside healthcare facilities, such as devices for home care, the HRI shall however appear on the label even if this results in there being no space for the AIDC. (MDR/IVDR Annex VI Part C 4.7).

Where in the MDR and the IVDR can you find basic information on the UDI system?
  • MDR Article 27 and Annex VI Part C
  • IVDR Article 24 and Annex VI Part C
Where else can you find information on the UDI?

Some other information resources are provided below:

  • MDCG 2022-7 – Q&A on the Unique Device Identification system under Regulation (EU) 2017/745 and Regulation (EU) 2017/746
  • MDCG 2018-1 Rev.4 Guidance on BASIC UDI-DI and changes to UDI-DI
  • IMDRF Unique Device Identification system (UDI system) Application Guide here.
  • Unique Device Identification System under the EU Medical Device Regulations
    2017/745 and 2017/746, What you need to know on the Europa website here.
  • Factsheet for healthcare professionals and healthcare institutions on the Europa website here.
  • US FDA UDI basics here including a sample label.
23 August 2022Section entitled Where else can you find information on the UDI? updated to include a link to the guidance document MDCG 2022-7