What is UDI (Unique Device identification)? Principles for system design and operation – medical devices

What is UDI (Unique Device identification)?

UDI is based on a sequence of numeric or alphanumeric characters created using worldwide accepted device identification and coding standards. Allows unequivocal identification of a device on the market. The UDI system was developed to facilitate adequate device identification through distribution and use on patients, adding the traceability of medical devices. The figure below illustrates an example of what UDI identification might look like (GS1 standard).

The figure below outlines the stages of UDI implementation.


UDI timeframes and deadlines vary by market and product and have been revised multiple times in some countries.

Although in Europe the guidelines began with the publication of the IMDRF in 2013, which we will discuss further, this was not new to the medical device industry as it has been a necessity for products exported to the US for many years.

In Europe, the UDI number will also be a requirement for product tracking, for which the EUDAMED database should be used.

In contrast to the USA and Brazil, an additional “Basic UDI-DI” is required for Europe. The Basic-UDI-DI (Basic Unique Device Identification - Device Identifier) is an identifier for medical devices in groups. with the same intended use, risk class, and essential design and manufacturing characteristics. Unlike the UDI-DI, which is specific to each device model and version, the Basic-UDI-DI does not appear on the product label or packaging. Instead, it serves as a key identifier in regulatory databases and documentation, ensuring traceability and facilitating regulatory processes.

Important: the regulated company should ensure that the UDI systems comply with the appropriate regulations. This is the role of the validation process. Explore our services page and discover how FIVE Validation can enhance your work!


International Medical Device Regulators Forum (IMDRF)

The IMDRF facilitates international multilateral cooperation to converge regulations concerning medical devices and Software as a Medical Device (SaMD). The goal is to promote adaptable strategies for addressing emerging challenges while ensuring the protection and enhancement of public health and safety. Its membership includes competent authorities from diverse countries committed to collaborating on regulatory harmonization efforts. IMDRF has several technical working groups that issue guides. One of them provides a framework for the regulatory authorities that intend to develop their UDI system in a globally harmonized approach (IMDRF/UDI WG/N7 Final: 2013) and another is to be used as a supplement to the first, which was developed as a high-level conceptual framework containing the basic core concepts of a UDI device (IMDRF/UDI WG/N48 FINAL: 2019).

What is on the label?

You can see an example of a linear bar code in the picture below.

Some of the numbers in the brackets on the UDI-PI component will be recognizable. Each of these numbers conveys specific details about the item:

(01) GTIN

(10) is for the lot number.

(11) is for the production date.

(17) defines the expiration date.

(21) is the serial number.


This means that every new batch or updated expiration date will have all of these details change, making the code dynamic.



The UDI is composed of two parts:


Production Identifier (UDI-PI)

therefore: UDI = UDI-DI + UDI-PI
Unique Device Identifier - Device Identifier (UDI-DI):
The Device Identifier of the UDI is a unique numeric or alphanumeric code specific to a model of medical device and that is also used as the "access key" to the information stored in a Unique Device Identification Databases (UDIDs). This mandatory, fixed portion of a UDI identifies a manufacturer’s specific product and package configuration.
Unique Device Identifier - Production Identifier (UDI-PI):
The Production Identifier of the UDI is a numeric or alphanumeric code that identifies the unit of device production when one or more of the following data is included on the package label of the device. The different types of Production Identifier(s) include:

a) The lot or batch within which a device was manufactured b) The serial number of a specific device
c) The expiration date of a specific device
d) The date of manufacture (may not be required if other Production Identifiers are on the label)
e) the version, applicable for Software as a Medical Device (SaMD)
Note.: SaMD version might be captured in the lot Production Identifier under certain national regulations.
f) The Distinct Identification Code (DIC), when applicable. This number is an essential identifier for medical products of human origin
Note.: Medical products of human origin (MPHO) include blood, organs, bone marrow, cord blood, corneas, tissues, reproductive cells and milk derived from humans for therapeutic use. The use of DIC in UDI is limited to MPHO products regulated as medical devices.
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 an identified UDI, has a device count greater than 1, a Unit of Use DI (UoU DI) shall be assigned.
UDI Carrier
shall be on the label or on the device itself and all higher levels of device packaging. Higher levels do not include shipping containers. The UDI carrier is the format in which the UDI can be shown.a) Automatic Identification and Data Capture (AIDC) is a technology used to automatically capture data. AIDC technologies include bar codes, smart cards, biometrics, and RFID (Radio Frequency Identification).
b) Human Readable Interpretation (HRI) is a legible interpretation of the data characters encoded in the UDI carrier. It´s important in case there is no automatic system to read the code.


The UDI-carrier therefore, should initially have a section that can be read automatically, like a bar code, and be followed by a part that can be read by humans, like numeric codes.

When the UDI system is fully implemented, the label of most devices will include a UDI in a human-readable form and an AIDC carrier.

The UDI is intended to be the identifiers also used in the context of business and clinical transactions, including traceability of devices in the post-market setting (e.g. purchase orders, invoices, inventory maintenance/management, clinical notes, etc.).

The UDI carrier shall be placed on the label of the device and all higher levels of packaging and in case of reusable devices on the device itself (direct marking).

Would you like to know more about the validation role in the UDI project? Please, contact one of our specialists at [email protected]



Software as a Medical Device - UDI assignment criteria

The UDI should be assigned at the system level of the Software as a Medical Device (SaMD).

The version number of the SaMD is considered the manufacturing control mechanism and should be displayed in the UDI-PI.

The following change of a SaMD would require a new UDI-DI:

  • Major SaMD revisions shall be identified with a new UDI-DI;
  • Major SaMD revisions are meant as complex or significant changes affecting:
    • the original performance and effectiveness,
    • the safety or the intended use of the SaMD.


These changes may include new or modified algorithms, database structures, operating platforms, architecture, or new user interfaces, or new channels for interoperability.


The following change of a SaMD would require a new UDI-PI (not a new UDI-DI):

  • Minor SaMD revisions shall be identified with a new UDI-PI;
  • Minor SaMD revisions are generally associated with bug fixes, usability enhancements (not for safety purpose), security patches or operating efficiency.
    • Minor revisions shall be identified by manufacturer-specific identification methods (e.g. version, revision number, serial number, etc.)"


You can see an example of UDI assignment to SaMD in the picture below.

What are the obligations of economic operators about UDI?

Manufacturers: shall be responsible for the UDI assignment and placement of the UDI carrier, the initial submission, and updates to the UDI databases. Manufacturers shall update the relevant database record within 30 days of a change being made to an element (deadline for Brazil, EU, and US), that does not require a new UDI-DI.

Distributors and importers: shall verify that, where applicable, a UDI has been assigned by the manufacturer.

Economic operators and health institutions: regulatory authorities might require that healthcare providers and retail pharmacies ensure that all device records they maintain include the UDI as an essential component to allow traceability of devices. This period normally is equivalent to the period for keeping patient records.

How can I get a UDI code?


A UDI can be obtained through one of the official issuing agencies operating worldwide. The health authorities accredit each UDI issuing agency in that region.


UDI Databases



Accepted issuing entities


To be established


European Union



United States





Brazil UDI requirement

On January 10, 2022, RDC 591/2021 was published. It provides for the identification of medical devices regularized at ANVISA (Brazilian Regulatory Agency), through the Unique Identification of Medical Devices (UDI) system.

Brazil compliance timeline

Device risk class

Compliance dates (labeling)

Class IV

10 Jul 2024

Class III

10 Jan 2025

Class II

10 Jan 2026

Class I

10 Jan 2028


European Union UDI requirements

To improve transparency and access to information, the European Database on Medical Devices (EUDAMED) has been developed. Initially, manufacturers were not required to register their medical devices on EUDAMED until all of its six elements (‘modules’) had been set up. However, three modules are already available, and two more are expected to become available in 2024. The final module is unlikely to be completed until late 2027.

While the European Commission is not in a position to require the use of the UDI/devices registration module until EUDAMED is fully functional, manufacturers can already enter UDI information in the system voluntarily.


European Union compliance timeline

Device risk class

Compliance dates (labeling)

Implantable and class III devices

May 26, 2021

class III and class IIb implantable devices ‘legacy devices’

Dec 31, 2027

Class IIa and IIb

May 26, 2023

Class I

May 26, 2025

Implantable and Class III - reusable

May 26, 2023

Class IIa and IIb - reusable

May 26, 2025

Class IIb devices and class IIa, class Im, and class Is ‘legacy devices’

Dec, 31 2028

Class I - reusable

May 26, 2027

Class D (IVD)

May 26, 2023

Class B and C (IVD)

May 26, 2025

Class A (IVD)

May 26, 2027


United States UDI requirements

The US FDA requires that all UDI information be entered into the US-specific GUDID database.

United States compliance timeline

Device risk class

Compliance dates (labeling)

Class III

Sept 24, 2014

Class II

Sept 24, 2016

Class II - reusable

Sept 24, 2018

Class I

Sept 24, 2018

Class I - reusable

Dec 8, 2022



Implementation of the UDI project - main challenges for validation professionals

Manufacturing and importing companies should plan the acquisition, qualification, validation, and technology of the solutions that will be part of the UDI project.

As you may know, medical device companies are highly regulated and need to prove that their development, processes, and final product are consistent. This is the role of validation and qualification.

Carrying out the validation will minimize project risks and ensure application compliance, avoiding regulatory agency sanctions.

The sooner companies prepare, the easier the availability and planning will be.

While it may seem like there is ample time to prepare (as EUDAMED is not fully functional), it is important to recognize that there are numerous intricate tasks that must be completed before the deadline.

For countries like Brazil, although the database has not yet been defined, all other requirements should be met, that is, companies must demonstrate compliance with their processes, their technology, and their information landscape.

Software/equipment used in implementing the UDI system (e.g. system used for UDI labeling, vision system, system for automatic data loading into the UDI database) should remain validated following the relevant regulations.

One of the main challenges for small and medium-sized industries is the lack of a highly skilled validation workforce.

Often, it takes time to train professionals in this area, which can delay product registration and production.

The UDI project involves a lot of technology; however, many companies still choose to carry out the validation in the traditional way, on paper, which makes the process time-consuming and bureaucratic.

This project has different characteristics, because it has several stages, according to the device risk class, this means that their respective validations may occur at different times in the project.

Paperless validation is the best solution and strategy. Validation should not be the “bottleneck” in the innovation and technology chain, but rather an ally to ensure compliance at each stage of the implementation and application.

Briefly, each device risk class that will be inserted may eventually include new equipment and systems and have different business rules or requirements.

This behavior is typical of a project that requires releases in phases, and multiple validation reports at different times.

GO!FIVE® has a partial release function to facilitate projects that have a single Validation Plan, and a single strategy, but distinct release phases.



Some advantages

As a way to make the project viable, we have complete solutions with experts (service provision) and software (paperless validation solution) to support projects anywhere in the world.

GO!FIVE® is a scalable SaaS platform, where it is possible to validate 6x faster following the agile method. It has over 15 years of consultancy knowledge within the software with pre-formatted validations built into it (risk, requirements, and tests).

GO!FIVE® meets FDA, EMA, and WHO requirements and allows agile projects:

  • Import validation templates for UDI project (requirement, risks, and test)
  • Validation 6x faster
  • AI capability for organizing PDF documents
  • Create/define items per line matrix
  • Partial releases
  • Ease of validated status maintenance
  • Test replication functionality
  • The only validation solution with qualitative content in the database

About the Author: Lílian Ribeiro

Lílian Ribeiro is a chemical engineer with a decade of technical and commercial expertise in the food industry, with a specialization in corporate quality and quality control. She also has valuable experience in the health and pharmaceutical sectors. As an advocate for paperless validation, she is passionate about introducing efficiency and innovation to life science companies. Lílian's extensive experience is instrumental in validation and qualification projects, encompassing VLMS, ERP, EQMS, automation (PW), and IT infrastructure qualification.

About the Reviewer: Silvia Martins

Silvia Martins is an electrical engineer with two decades of experience in the biopharmaceutical and medical device sectors. She has received training in GAMP5 and FDA 21 CFR Part 11 in England, SAP® validation in Germany, and has expertise in data integrity and data governance gained in Denmark. As the CEO and co-founder of FIVE Validation, a company committed to simplifying compliance processes, Silvia is dedicated to expediting and streamlining procedures for clients while maintaining a high level of robustness and compliance.

IMDRF/UDI WG/N48 FINAL: 2019 - IMDRF – Unique Device Identification system (UDI system) Application Guide, 2019:
IMDRF/UDI WG/N7Final: 2013 - UDI Guidance: Unique Device Identification (UDI) of Medical Devices