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udi Unique Device Identification Medical Device Regulation MDR 2017/745 2017/746

The UDI or “Unique Identification Number” Europe (as there is also one in the USA) is one of the new things that come with the new EU MDR 2017/745 and IVDR 2017/746.

This element will be key for the traceability of devices in Europe.


To be specific, the concept of UDI did appear on the IMDRF guidance issued in 2013. This defined the basis of this new technology.

Nowadays, it´s not something new for the Medical Device Industry as it´s also a requirement for products delivered to the US market.

But for manufacturers that are not selling their products in the United States of America, there will be some work to do.


The UDI number is important because it will be needed for tracking your product. For that, we should use the EUDAMED database. 

I know, this is still not in place and we don´t know when it will be. 

The UDI will be key as it´s one of the primary numbers to identify your product on this database.

Why so late

I was initially expecting to issue this topic when there will be more clarity on EUDAMED or the companies that will be allowed to provide the identification numbers.

But I discovered after reading many times the EU MDR that the commission already designated some companies if I can say (lol).

So, I decided to provide you with the information I have now and maybe, update this article when there will be more information later.

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Table of Contents

What is the UDI or Unique Device Identification?

This is a number that identifies a specific product. On the UDI that is on your product, there are 2 parts which are:

  • The UDI-DI
  • The UDI-PI

The UDI-DI is the device identifier. It identifies a specific device on your portfolio. This is the static part of the UDI number. It doesn´t change within the same exact product. But we´ll go more deeply on that on the next chapters.

The UDI-PI is the production identifier. It is the dynamic part of the UDI. It tells you about lot number, serial number, manufacturing date, expiration date…

But before that, you need the Basic UDI-DI which identifies a group of product. It´s different from the UDI-DI.

And also the UDI carrier. Ok, I stop.

Are you confused now?

I know it´s not simple to digest all this. So, let´s review each of these ones, one by one. And as I am trying to make it easy for you I´ll illustrate this post with multiple examples.

Example of UDI

As I see that you are confused, I propose that we look at one example.

The UDI can be available in many forms. This is something we will see in the chapter related to the UDI Carrier. It can be a linear bar code as you can see on the example below.

But a legible part should be available. We call it also HRI or Human Readable interpretation.

As said previously, you can see the UDI-DI which is the number after the (01). Each time when you´ll see the 01 between brackets, this means this is the placeholder for the UDI-DI.

Now we arrive at the UDI-PI part. As mentioned, this part can vary as it depends on the production characteristic of the product.

You can identify some numbers in the bracket on the UDI-PI part. Let´s decode them. Each of these numbers is providing specific information about the product:

  • (10) is for the lot number
  • (11) is for the production date
  • (17) defines the expiration date.
  • (21) is the serial number.

All these information are dynamic as they change each time you have a new batch or a new expiry date…

UDI Unique Device Identifier Medical Device Regulation

What is the Basic UDI-DI?

Something that a lot of people were asking is about Basic UDI-DI. I think it created a lot of confusion, so I´ll try to clarify that.

If you are looking at Annex VI Part C of the MDR 2017/745 and IVDR 2017/746, it will provide you with a general definition of what it is. But not so much for me. The other resource that you can check is the MDCG 2018-1 Draft Guidance on Basic UDI-DI. This provides a bit more information that I will summarise here.

The Basic UDI-DI is an identification number that is not for a specific product but for a Group of products.

It has no supply chain value. It´s only used for administrative purposes. If you prefer, it´s like you are creating an identification number for all your Contact lenses. You can have many of them on your portfolio.

One Basic UDI-DI is for devices within the same category:

  • Intended purpose
  • Risk class
  • Essential design
  • Manufacturing characteristic

And then when should the Basic UDI-DI appear?

You´ll have it on your:

Surprise. This one does not appear on the packaging of the products. It´s really an invisible number for your customers. It´s only for the administration.

And under this Basic UDI-DI, you will have one or many UDI-DI (Specific product identification).

Decision Tree (Medtech Europe)

To help you group your products, Medtech Europe created this guideline that contain a Decision Tree. If you follow that this will provide you with all the support needed to succeed at attributing a Basic UDI-DI to your products.

Medtech Europe Basic UDI-DI decision tree - EU MDR and IVDR

UDI Checklist

To help medical device manufacturers to comply with the MDR 2017/745 requirements regarding UDI, I created this checklist.

This is containing all the information that will help you setup your UDI information.

Have a look!

Where can I get the Basic UDI-DI?

The UDI, in general, is provided by an official designated entity. I mean, the designated entity will provide you with the tools to create your Basic UDI-DI.

The designation should be done by the Commission if you are looking at Article 24(2).

But let´s look at that in the next chapters.

What is the Format of a Basic UDI-DI?

On the MDCG 2019-1 guiding principles of issuing entities rules on Basic UDI-DI, we can see that there are some requirements to follow.

To be as clear and efficient as possible it is required that the Basic UDI-DI format should be as close as possible to the UDI-DI that you’ll see on next chapter.

  • Maximum of 25 characters as this is the maximum length of the UDI-DI
  • The organization that will provide you the UDI code should also implement a check digit/character. And they should provide  an algorithm (to the Commission and the manufacturer) to verify the code.

Security of the code start to increase. The question I am asking myself is if this check digit/character is visible to anyone or if this should be kept secret… Maybe someone to answer on the comments. 

What is the UDI-DI?

I know it´s not finished. Every Medical Device manufacturers will need to understand this process as it´s critical for them to be compliant.

Now that you have your Basic UDI-DI for your group of products. You need a UDI-DI for each product.

Let´s continue with hip implants. Your group of hip implants does have a Basic UDI-DI. This is what we saw previously. And on this group, you have 3 categories of Hip Implants. COa, COb, and COc.

I think it´s still clear for now.

So you´ll have the same Basic UDI-DI for the 3 hip implants and One UDI-DI for each hip implants.

  • COa – UDI-DI 1
  • COb – UDI-DI 2
  • COc – UDI-DI 3

I think an image is worth many words so let´s draw this situation.

How to create your UDI-DI & Basic UDI-DI?

To help you create your Basic UDI-DI and UDI-DI, I have asked Sylvia Reingardt from GS1 to help.

She accepted to show us how you can by yourself define the UDI codes for your product.

This video is showing some practical examples. You can look on the show notes for the links to generate the codes.

Technical Documentation Templates

GSPR Template MDR 2017/745
  • Template compliant to requirements of MDR 2017/745 Annex II and III.
  • Formatted with the chapters already defined.
  • Guidance provided to help you identify the content to include
  • General Safety and Performance Requirements compliant to Annex I.
  • Include guidance to prove evidence to the requirements.

UDI-DI in case of changes

If you make some changes to your products, the UDI-DI that you received for it can be subject to a change.

What are the cases when a UDI-DI needs to change?

So a new UDI-DI will be required if you change:

  • Name or trade name
  • Device version or model
  • Labeled as single use
  • Packaged sterile
  • Need for sterilization before use
  • The number of devices in a package
  • Critical warning or contra-indication
  • CMR / Endocrine disruptive
  • Colour
  • Language

Ok, let´s pause a moment. This can mean that the same product delivered on different packaging quantity or on different state (Sterile, non-sterile, single use) will have different UDI-DI.

Let´s illustrate that below with our previous example. If we create for example many versions of product COa:

  • Sterile version
  • To be sterilized version
  • Packaged per 10 pieces

How many UDI-DI do we need? You have 1 hour to answer 😉

Oh sorry, I forgot to remove the solution on the graph below.

UDI-DI Different version of packaging - EU MDR 2017/745 EU IVDR 2017/746

So to conlcude on that, you´ll need a  UDI-DI for each version of your product which will be linked to one Basic UDI-DI.

Let´s look at that on the pyramid below.

Basic UDI-DI and UDI-DI pyramid EU MDR 2017/745 and IVDR 2017/746

I know I repeat myself sometimes but I think you really need to understand. But, I am not done. Sorry.

Now we will talk about the UDI-PI

What is the UDI-PI?

The UDI-PI stands for Unique Device Identification – Production Identifier. Ok doesn´t tell you much.

Imagine you are in 2018 and you are manufacturing Product A Version 1.

  • The first day, on March 15th you produce a quantity of 5 pieces.
  • Then March 16th, you produce another batch of the exact same product with 3 pieces.
  • Then March 17th and 18th you produce nothing (as it is the weekend – I am sure you will check if this matches lol)
  • And you restart on March 19th with 2 pieces.

So what do we have now?

We will have this configuration.

  • March 15th: We will have 5 pieces with on their label the UDI number: UDI-DI A1 – UDI PI (15/03/2018, Batch number #1,…)

So, this first batch has 5 pieces that have the exact same UDI-DI and UDI-PI as they are from the same batch.

  • March 16th: 3 pieces with UDI-DI A1 – UDI-PI 1 (with manufacturing date:16/03/2018, Batch number #2,…)
  • March 19th: 2 pieces with UDI-DI A1 – UDI-PI 2 (with manufacturing date: 19/03/2018, Batch number #3,…)

You have produced 3 batches with products that have the same UDI-DI but for each batch, it has a different UDI-PI.

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Ok, I think you didn´t expect to see so many vocabularies for the UDI. And to be honest this is nothing as we just touched the product. But one last vocabulary that you´ll need to understand is the UDI-carrier.

This is the format you can see the UDI. And there are 2 parts also for it the AIDC and the HRI:

Automatic Identification and Data Capture (AIDC) = It is a technology used to automatically capture data. AIDC technologies include bar codes, smart cards, biometrics and RFID (Radio Frequency Identification).

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.

So the UDI-carrier is the way you are seeing the UDI code. So first it should have an automatic readable part like a bar code and a human-readable part like numeric codes.

Are you ok! Still following.


UDI is an information that is required for the EUDAMED.

What is EUDAMED? This is a new database that is required by the new MDR 2017/745 and IVDR 2017/746. On this database you should register your company, and also your products. 

Without that, you cannot use it. Or, no, you can still use it with the products still valid under MDD.

But let´s speak with an expert in EUDAMED so he can explain to you what it is and how this is working. Richard Houlihan from was my guest on episode 25 of my Podcast.

For your information, EUDAMED was planned to go live on March 2020 but the European Union decided to delay its implementation until May 2022. But MDR is still planned for May 26th, 2020. (SOURCE)

I invited Richard Houlihan on episode 50 of the Medical Device made Easy Podcast help us understand about the consequences of this delay.

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As I know there are a lot of questions between UDI and EUDAMED, I wanted to provide you more information so you get prepared.

Here is the link related to the different fields that should be filled on EUDAMED specifically for UDI data.

Legacy devices

You maybe ask yourself, “What is a legacy device?”. During the transition period from May 26th, 2021 until May 26th, 2024, there will be a mix on the market. Both MDD and MDR products will be placed on the market but some rules applicable to MDR will also need to be executed by MDD products.

For example, any vigilance reporting should follow the MDR requirements even if it is an MDD product. But one of the requirement when you report a vigilance issue is to identify the product with its UDI number.


MDD product are not obliged to have a UDI code as this is only a requirement for MDR products. So how can we track the product on the EUDAMED database?

The EU Commission defined the rules to apply.

I know that this doesn’t look easy for you when you read the document. But no worry. I have invited someone to help us.

We discussed this situation with Richard Houlihan from on a Live. See below.

Richard created a template to help you generate the codes which are called EUDAMED-DI and EUDAMED-ID.

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UDI vs Primary packaging and Secondary packaging

I did receive an interesting question related to primary packaging and secondary packaging of a product. Do you need to have 2 UDI-DI? One for the primary and one for the secondary.

My answer to this is no as we are still on the same level.

Packaging levels means the various levels of device packaging that contain a defined quantity of devices, such as a carton or case.

In the case of a bottle with its own label (primary packaging) and the carton that protect this bottle with also information about the product inside (secondary packaging) we are still at the same packaging level. So, you should not consider it as 2 levels.

You will be considering it as 2 levels if you have 2 bottles in 1 carton for example. Maybe the 2 bottles were not manufactured the same day and are packed during another process. Each bottle has its own UDI-PI. So then we have a second level.

On our initial case, the UDI-DI and UDI-PI of the product is the same on the primary and secondary packaging. The quantity of product is 1 unit per secondary packaging. So the all remain 1 Unit.

UDI carrier on each level

But do you need to see the UDI appear on the bottle and the secondary packaging.

On Article 27(4), it says:

UDI carriers shall be placed on the label of the device and on all higher levels of packaging. Higher levels of packaging shall not be understood to include shipping containers.

So, for a same product that has a primary and secondary packaging its only 1 UDI for both. And those UDI should appear on the primary and secondary packaging.

Where can I register for the UDI?

This is the tricky part. Normally you need to contact an entity that is authorized to provide you with UDI-DI code. This is the code that is specific to your company and specific to your products.

As you understood in the previous chapters, you can need many codes depends on your portfolio.

The European Commission should designate the companies that are authorized to provide this UDI-DI number.

On Article 120(12) of MDR 2017/745 it says:

“Until the Commission has designated, pursuant to Article 27(2), issuing entities, GS1, HIBCC and ICCBBA shall be considered to be designated issuing entities.”

And when you look at article 27(2), it defines what are the requirements that these companies should comply with.

So if I interpret this sentence correctly, the commission is looking for the companies that will be designated, but anyway, GS1, HIBCC, and ICCBBA are considered to be designated issuing entities.

In reality, the companies mentioned are already providing UDI-DI for the US manufacturers. So the decision of the EU commission is logic when they say that those companies are already qualified as this is a real step forward to the worldwide harmonization.

But, recently new information was issued by the European Commission.

What’s new?

On June 6th, 2019 a Commission Implementing Decision (EU) 2019/939 was issued. On the annex, a list of designated entities is provided :

So you have here the official list of entities that are designated. Maybe more will come later. The IFA GmbH is a new entity as this was not listed in the article 120(12).

FDA resources

As FDA already implemented UDI for its products, why not having a look at the resources they already provide to its manufacturers.

UDI Format guidance

The European Commission issued some guidance for each designated entity that was mentioned before.

When you’ll identify the entity that will provide you with your UDI, you can then look at its specific format.

The concept of UDI-DI, UDI-PI, Basic UDI-DI doesn’t change but the number of letters or numbers is unique to them.

This can help also to identify which entity did supply you with the UDI number for your Medical Device.

Designated entities

Guidance Documents


Sylvia Reingardt from GS1 Germany accepted to come to my Podcast. We discussed all the aspects of the UDI codes. If you want to have a better understanding then you should check episode 86.

Where should I place the UDI on my product?

There are some rules for where should the UDI be visible. Normally the code should be visible for the person that is using the product. 

By the dates that you will see in the chapter “UDI transition period” you´ll need to place the UDI carrier on the label of the device and on all higher levels packaging.

But there are certain cases where it can be different.

For example, for class I and IIa single-use devices, packaged and labeled individually. In that case, the UDI code can be placed not directly on the primary packaging, but on the next higher packaging. This packaging can contain several of these individual package products.

For reusable devices, the UDI should be directly marked on the product. It´s true that there are few exceptions (If space doesn´t allow that for example)

For this last case, the EU is different than the US. FDA authorize to have the AIDC or the HRI. But in the EU both should be visible. 

UDI for combination products

What is a combination product?

This is a product that combines many regulations.

For example a product that contains both a Medical Device and a Drug. Or a Drug and Cosmetic…

But the product will mainly follow only one regulation. This depends on the intended use.

UDI or not UDI?

If you have Combination products, then you need to understand if UDI is applicable to your product.

On the MDCG 2019-2, you can see the rule to apply.

To summaries the guidance, I can say that if your product is a Medical Device but incorporate a medicinal product, you have to comply with the UDI requirements.


  • Catheters coated with heparin or an antibiotic
  • Soft tissue fillers incorporating local anaesthetics
  • Implantable infusion pump
  • Spacer devices for use with metered dose inhalers
  • Bone void filler with an antibiotic
  • Bone void filler with animal growth factors, where the action of the growth factors is demonstrated to be ancillary to that of the physical filler

But if your product is regulated by the Medicinal Directive 2001/83/EC, the medical device part of it can use or not UDI. This means it’s not mandatory.


  • Non-reusable autoinjectors containing a medicinal product as integral part
  • Nebulizers precharged with a specific medicinal product
  • Patches for transdermal drug delivery
  • Wound dressings impregnated with an antibiotic, where the primary intended
    purpose is to administer the antibiotic to the wound
  • Bone void filler with animal growth factors, where the action of the growth
    factors cannot be demonstrated to be ancillary to that of the physical filler

UDI for standalone software

It can be disturbing to talk about UDI for something that is immaterial. But the EU MDR also provided some information on how to handle this with Softwares. Let’s dig on this.

Which software is on focus?

The only software that can be commercialized alone is on the scope of Annex 6 Part-C paragraph 6 of the EU MDR.

The rule for UDI-DI and UDI-PI

Similar to other products, a software UDI should have the 2 parts (UDI-DI and UDI-PI)

The manufacturing parameters should be displayed on the UDI-PI and the general information about the software on the UDI-DI

Software changes vs UDI change

As you may know, software is constantly maintained. So what to do with the UDI number for each type of changes.

In the case of Minor changes, like some bug correction, usability enhancements without safety purposes, security patches or operating efficiency; you as a manufacturer should change only the UDI-PI.

For example, the lot number or the serial number…

But in case of Major changes, then you need to ask for a new UDI-DI.

Which Major changes require a new UDI-DI?

There are 3 cases defined on the MDR where you’ll need to change the UDI-DI number. Let’s list them:

  • The original performance
  • The safety or the intended use of the software
  • the interpretation of data

All this can include new or modified:

  • Algorithms
  • Database structures
  • operating platform
  • architecture or new user interfaces
  • or, new channels for interoperability

Where should be placed the UDI number?

This one is interesting as this is a question that a lot of people are asking. Where on software should we write the UDI number?

There are multiple places:

Physical medium

If you deliver your software on a CD or a DVD, you should then place your UDI number on the packaging as HRI and AIDC.

The UDI linked to your system level software should be the same as the one to your packaging level.

Software with User Interface

If your software can be displayed on a computer screen, for example, you should make the UDI HRI plain-text format available on the start-up screen or as an ‘about’ file.

Software without User Interface

Software that is not displaying images should be able to transmit the UDI through an application programming interface (API).

Below are some other rules to apply for UDI on a software


For electronic displays, only the HRI (Human Readable Interface) is required. 

AIDC is not required. But if you want to include it, knowing that there is no risk to miss the HRI part, you can.

Application identifiers (AI)

The UDI human readable format should also include the Application Identifiers. This is the standards used by the issuing entity to help identify how this UDI number was created.

Guidance MDCG 2018-1 v2

The European Union issued an update of its MDCG guidance (Medical Device Coordination Group) related to UDI:

The items discussed are:

  • The Basic UDI-DI
  • Link between Basi UDI-DI and Certificates or Declaration of Conformity
  • Changes of UDI-DI

To review the details of this Guidance you can click on the button below.

Let´s repeat again

If we summaries.

Basic UDI-DI is an administrative code used only for the company that is manufacturing the product to be identified by the authorities and also to group devices that are part of the same category. You can get that from the same entities as the one that provides you the UDI-DI.

The UDI of the product is composed of the UDI-DI (Device Identifier) which is a fixed part that you get by registering with an official entity (GS1, HIBCC, ICCBBA).

And the UDI-PI (Production Identifier) which is the dynamic part related to the product itself (Lot number, expiry date, serial number…)

This UDI on the product should be available through the UDI-carrier which is the way we are seeing the UDI. In our case, it should appear to us under 2 format:

  • Automatic Identification and Data Capture (AIDC)
  • Human-readable Interpretation (HRI)

Both formats should be visible. The AIDC should be used for any automatic device that can scan the code. And the HRI should be understandable by humans (It´s in case the automatic device is not working).

And finally, for combination products, if your product is regulated as a Medical Device then you need to apply UDI. But in case your product is regulated as a Medicinal Product that incorporates a Medical Device, then it’s not mandatory to apply UDI

EU UDI transition period

I see that you are not feeling well reading all these requirements. But I hope this chapter will provide you with more relief.

The UDI requirements are not to be implemented immediately. Or to be more precise, this depends on the classification of your product.

Let me explain you.

The UDI requirement depends on the risk of your product. So more there is a risk, sooner you should implement it.

Below are the implementation dates following the class:

  • Class I: 26 May 2025
  • Class IIa and IIb: 26 May 2023
  • Class III: 26 May 2021
  • Implantable devices: 26 May 2021

One last point. For Reusable devices, like surgical instruments, The UDI carrier should be on the product and as there are some products that will be already on the market, the European Commission is delaying it´s implementation to 2 years later (Depends on the class).

If the reusable product is class III, then the implementation of UDI is delayed to 26 May 2023.

If it´s classification is class I, then this can be implemented until 26 May 2027.

If you want to check the sources, you can go to the MDR 2017/745 article 123 (3f) and (3g)

UDI Infographic

UDI Helpdesk

The EU Commission has created a webpage to help you have a better understanding on UDI. 

This webpage is presenting some sections as:

  • Definitions and basic information
  • Specific questions
  • EUDAMED-related questions
  • Dates and deadlines
  • Documents and links.

You can also submit your request about UDI if there are some information missing. So don’t hesitate to use the “Submit a request” button.

Check this website on the link below.


Are you able to answer these questions? 

If yes then you understood a good part of what is the UDI for medical devices in Europe.

Question 1

What are the 2 parts of the UDI number visible on the product?


The UDI-DI (Device Identifier) which is the fixed part and the UDI-PI (Production Identifier) which is the dynamic part.
Click Here

Question 2

Where can you get the UDI-DI and the Basic UDI-DI?


From entities designated by the European Commission. From Article 120(12), there are already 3 entities that are mentioned (GS1, HIBCC, ICCBBA).
Click Here

Question 3

Can the UDI be only visible as a barcode?


No, it should be visible both in machine readable and human readable part.
Click Here

Question 4

Is the Basic UDI-DI visible on the product?


No, it is visible on the documentation linked to the product (Declaration of conformity, technical files…)
Click Here

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Just one question for you. This would help me to understand your situation. See the question below.


Have you already implemented your UDI barcode on your products?

Answer on the comment

I am really interested to hear about your answer. Let me know if this was difficult and if you have done it alone or asked a company to help you.
Beginners Guide:  UDI or Unique Device Identification (EU MDR and IVDR)
Article Name
Beginners Guide: UDI or Unique Device Identification (EU MDR and IVDR)
The UDI is one of the new innovation that comes with the new Medical Device Regulation MDR 2017/745 and also the IVDR 2017/746. On this article I tell you what you need to understand how to implement this new tool.
Publisher Name
Easy Medical Device
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Categories: Compliance

Monir El Azzouzi

Medical Device expert. Monir founded Easy Medical Device to help Medical Device companies to place compliant products on the market. He proposes his consulting services so don't hesitate to contact him at or +41799036836 My objective is to share my knowledge and experience with the community of people working in the Medical Device field.

UK Representative from January 1st, 2021

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