UDI stands for Unique Device Identification. It is an identification system for medical devices (UDI) designed to give them a positive, unique and globally harmonised identification each time. This system requires that the label on medical devices contain this unique identification when the products are distributed and used, that it is transferable using automatic identification and data collection, and that its meaning is human readable if necessary. The UDI-DI (device identification code) is also linked to a public UDI database, specific to jurisdiction.
A UDI consists of a combination of a Device Identifier as unique identifier (GS1 product code/GTINs) and one or more Production Identifiers (Application Identifiers (AIs)).
Article code/GTIN: AI (01)
Best before date: AI (17)
Production date: AI (11)
Batch/lot number: AI (10)
Serial number: AI (21)
In healthcare, medical device manufacturers generally use the Application Identifiers (01) GTIN, (17) Expiry Date, (11) Production Date, (10) Batch or Lot Number and (21) Serial Number. The AIs let systems know what information follows (e.g. AI (01) indicates that the GTIN follows and AI (17) that an expiry date follows). The manufacturer incorporates the AIs into the symbol and as human readable form (HRI) text.
The US Food and Drug Administration (FDA), the European Commission and other regulatory bodies put patient safety at the centre of the development of UDI regulations for medical devices and in-vitro diagnostics (IVDs) and strive for a globally harmonised and consistent approach, aligned with the guidelines of the International Medical Device Regulators Forum (IMDRF).
GS1 awards UDIs as an agency/entity and is recognised by several authorities worldwide, including the United States, the European Union, China, South Korea and Saudi Arabia. This means that manufacturers supplying regulated medical devices to these markets use GS1 standards to implement UDI requirements.
The GS1 standards system provides a global framework for identifying, capturing and sharing information of healthcare products, enabling consistent UDI implementation worldwide.
You can create your UDI-DI automatically using My Product Manager.
A UDI must be placed on the product label (on the packaging and sometimes on the medical device itself). A UDI is also placed on all higher packaging levels. In human readable form: Human Readable Interpretation (HRI). In symbol form: in the form of a barcode (Automatic Identification and Data Collection - AIDC)
No restriction is foreseen in MDR and IVDR for using different issuing entities to assign the Basic UDI-DI and the UDI-DI to a device.
As regards the registration of the device in EUDAMED, the Basic UDI-DI information is linked to the UDI-DI information identified on the first packaging level. The current existing data dictionary for the data elements allows for the Basic UDI-DI to have a different issuing entity than the UDI-DI.
The UDI-PI information is not required to appear on the label in AIDC format on the point of sales packaging if the device is exclusively sold at retail point of sale. The MDR 2017/745 excludes the UDI PI information from AIDC format on the point of sales packaging level, however, the exception is not applicable for the HRI, which needs to be identified on the point of sales packaging. The mentioned exception is defined for the sales packaging level only, so the primary packaging level must be in compliance with UDI requirements as defined in MDR (UDI-DI and UDI-PI in both AIDC and HRI format.) Reference: Annex VI, part C, section 4.4:
For devices exclusively intended for retail point of sale the UDI-PIs in AIDC shall not be required to appear on the
The UDI-DI is a unique numeric or alphanumeric code specific to a model of device and that is also used as the ‘access
key’ to information stored in a UDI database. The UDI-DI shall be unique at each level of device packaging.
This mandatory, fixed portion of a UDI identifies a manufacturer’s specific product and package configuration.
The Unit of Use DI (UoU DI) is an identifier (following the UDI rules of the chosen issuing entity) assigned to an
individual medical device when a UDI is not labeled on the individual device at the level of its unit of use. Its purpose
is to provide a UDI-DI to identify a device used on a patient when a UDI-DI does not appear on the label of the device.
For example: If the lowest base packaging level with a identified UDI, has a device count greater than 1, a Unit of
Use DI (UoU DI) shall be assigned.
If the device is not directly marked and the base quantity of the device is greater than one, the Unit of Use DI shall
be provided within EUDAMED. The Issuing entity for the Unit of Use DI Code is the sameas the UDI-DI.
The same Unit of Use DI can be used for several Devices. According to Annex VI, part C, section 1, the Unit of Use-DI is defined as follows:
The Unit of Use DI serves to associate the use of a device with a patient in instances in which a UDI is not placed
on the individual device at the level of its unit of use, for example in the event of several units of the same device
being packaged together. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32017R0745
Please refer for further details to:
“Appendixes E-I of IMDRF N48 under the EU regulatory framework for medical devices” (May 2021; MDCG 2021-10) https://ec.europa.eu/health/system/files/2021-06/md_2021-10_en_0.pdf
According to Annex VI, part C, section 4.10, the rules and exemption for the UDI carrier are defined as follows:
Devices that are reusable shall bear a UDI carrier on the device itself. The UDI carrier for reusable devices that
require cleaning, disinfection, sterilisation or refurbishing between patient uses shall be permanent and readable
after each process performed to make the device ready for the subsequent use throughout the intended lifetime
of the device. The requirement of this Section shall not apply to devices in the following circumstances:
Any type of direct marking would interfere with the safety or performance of the device;
The device cannot be directly marked because it is not technologically feasible.
The UDI carrier is the means of conveying the UDI by using AIDC and, if applicable, the HRI. The UDI carrier (AIDC and HRI representation of the UDI) shall be placed on the label or on the device itself and on all higher levels of device packaging. It is noted that single use devices are not covered by this requirement.
The UDI information for SW medical device must be provided in addition to the regulatory required information for the SW medical device in question. The assignment criteria for the UDI carrier are defined in Annex VI, part C, section 6.5 as follows:
6.5.1 The UDI shall be assigned at the system level of the software. Only software which is commercially available on its own and software which constitutes a device in itself shall be subject to that requirement. The software identification shall be considered to be the manufacturing control mechanism and shall be displayed in the UDI-PI.
6.5.2 A new UDI-DI shall be required whenever there is a modification that changes:
a. the original performance;
b. the safety or the intended use of the software;
c. interpretation of data. Such modifications include new or modified algorithms, database structures, operating platform, architecture or new user interfaces or new channels for interoperability.
6.5.3 Minor software revisions shall require a new UDI-PI and not a new UDI-DI. Minor software revisions are generally associated with bug fixes, usability enhancements that are not for safety purposes, security patches or operating efficiency. Minor software revisions shall be identified by a manufacturer-specific form of identification.
6.5.4 UDI placement criteria for software
a. where the software is delivered on a physical medium, e.g. CD or DVD, each packaging level shall bear the
human readable and AIDC representation of the complete UDI. The UDI that is applied to the physical medium containing the software and its packaging shall be identical to the UDI assigned to the system level software;
b. the UDI shall be provided on a readily accessible screen for the user in an easily-readable plain-text format, such as an ‘about’ file, or included on the start-up screen;
c. software lacking a user interface such as middleware for image conversion, shall be capable of transmitting the UDI through an application programming interface (API);
d. only the human readable portion of the UDI shall be required in electronic displays of the software. The
marking of UDI using AIDC shall not be required in the electronic displays, such as ‘about’ menu, splash
The Basic UDI-DI is required to identify a medical device as a product family. Basic UDI-DI is a term used by the European Commission. Global Model Number (GMN) is the standard that GS1 has developed for this purpose.
For the Basic UDI-DI, GS1 has developed the standard Global Model Number (GMN). The manufacturer of the medical device is responsible for creating the Basic UDI-DI. You can calculate this number with the calculation tool. To do this, you need a company number from a GS1 code package. Take the company number from your code package, add an internal model reference to it and the calculation tool will then calculate 2 control characters across the board. For the internal model reference, you can use any digits and letters from Figure 7.11-1 in the GS1 General Specifications. In total, the GMN may not contain more than 25 characters (23 + 2 control characters).
The UDI is the unique product identification and is different for each product with, for example, a different content, language, shape or colour. Using the GS1 GTIN Allocation Rules, you can determine how many product codes you need. A Basic UDI-DI identifies a group of products, in which each product in the group has its own UDI. The UDI must be printed on the product in barcode format; the Basic UDI-DI is not printed on the product packaging.
The internal model reference is compiled by the manufacturer. Numbers, letters and characters can be used. For an overview of the characters that can be used for the internal model reference, see Figure 7.11-1 in the GS1 General Specifications.