UDI Differences – US and EU

The Unique Device Identifier (UDI) in the EU and the US differs in some points. On September 24, 2013, a directive was passed in the United States to introduce an identification system for MedTech products, which came into force on December 23 of the same year. It comes in the form of the Unique Device Identifier (UDI) and is intended to simplify the tracking of medical devices sold in the United States. In April 2017, the European Union followed suit with the Medical Device Regulation (MDR) and the In-vitro Diagnostic Regulation (IVDR). The EU-MDR came into force on June 21, 2017. They define the conditions for the EU’s UDI system. The requirements of the respective markets/regions are not uniform, making 1-to-1 implementation between regions impossible for medical device manufacturers.

Despite efforts to implement uniform standards for the UDI worldwide, the requirements in the U.S. and the EU differ in many ways. Differences within the two regulations relate to compliance dates, product classification, databases used, and required product data. In addition, the European Union has also introduced the Basic UDI-DI for identifying similar products of a manufacturer, which does not exist in the US. Furthermore, the GUDID has been fully operational for years, whereas two modules are still missing from EUDAMED as of September 2026.

Product classification and compliance dates

There is a difference between the regions’ product classes. In the EU, there are classes I, IIa, IIb, III, and reusable as well as implantable devices. The FDA’s Center for Devices and Radiological Health (CDRH) distinguishes between classes I, II, III, and LS/LS. Each class has its date for mandatory application of the regulations, depending on the region.

 

The UDI-databases: EUDAMED and GUDID

Both regulations require manufacturers to store information about their medical devices in a database. This makes them identifiable and provides important information for patients and other stakeholders. In the USA, this database is called the Global Unique Device Identification Database (GUDID), while the European equivalent is called the European Database on Medical Devices (EUDAMED).

The EUDAMED consists of 6 modules that are connected. The GUDID, on the other hand, is structured as an independent database. It is used solely for UDI and product master data management. In this respect, it is comparable to the UDI module of EUDAMED. The European database takes a significantly broader approach and, with its six modules, forms an important component of market surveillance and manufacturer transparency. In addition to UDI master data and information on individual economic operators, EUDAMED also covers certificates, vigilance, clinical trials and market surveillance mechanisms. Both databases – AccessGUDID and EUDAMED – are partially accessible to the public and make some of the data available to users, hospitals and distributors. Not all data is publicly accessible.

There are different formats for data exchange, depending on the database. The EU uses Extensible Markup Language (XML), while the U.S. uses Health Level 7 (HL7) Structured Product Labeling (SPL). Manufacturers can submit device information via both the GUDID web interface and electronic SPL submissions. XML files must comply with the HL7 SPL format specified by the FDA. Similar requirements apply to electronic submissions to EUDAMED via the XML bulk upload or the direct M2M connection.

How do the European and US UDI differ?

The UDI is a numeric or alphanumeric code for identifying medical devices. It consists of the UDI Device Identifier (UDI-DI) and the UDI Product Identifier (UDI-PI). The UDI-DI is a unique code and is used for item identification. In addition, it provides access to the respective database in which the product data and, if applicable, other documents are stored. For the American database, there are 28 required, 24 conditionally required, and 15 optional product attributes stored. For the European database, depending on the type of product, there are 59 required, 20 conditionally required, and 5 optional specifications. Both databases operate on the basis of the UDI-DI and not at the PI level. This means that the databases do not enable traceability down to the item level.

The structure of the UDI from the USA and the EU is indistinguishable. On the products, they consist of machine-readable and human-readable parts. Machine-readable means that it may be a linear barcode or a 2D barcode. For humans, the code consists of numeric/alphanumeric UDI-DI and UDI-PI. The UDI-PI may include lot number, serial number, expiration date, and production date, thereby enabling traceability of an individual medical device. Furthermore, the UDI-DI serves as a link to the EUDAMED (EU) and GUDID (US) databases and is thus, the access key to the information stored there. In the European Medical Device Regulation (MDR) a distinction is also made between Basic UDI-DI and UDI-DI. Although the UDIs have the same structure, they cannot be used parallel for both regulations.

Basic UDI-DI: Newly introduced with EU MDR and EUDAMED

In addition to the UDI-DI, the EU has introduced another, superordinate identifier. The Basic UDI-DI. While the regulation for the United States only requires the assignment of the UDI-DI itself, the Basic UDI-DI is additionally required in the EU. It does not identify a single product but serves as a parent category for various products of one category that share certain characteristics. An example: A manufacturer wants to produce a medical thermometer in three different versions. A yellow one, a red one, and a blue one. Each of the three thermometers is given its UDI-DI. However, these three versions of the thermometer share a single Basic UDI-DI because they belong to the same category. In the U.S., each thermometer receives only its UDI-DI and is not categorized.

	EU-UDI	US-UDI
Compliance dates	See above	See above
Data base	EUDAMED	GUDID
Data format	XML	HL7-SPL
Responsibility for assigning UDI	Manufacturer	Labeller*
Data base access key	Basic UDI-DI	UDI-DI
Possible UDI-DI attibutes	84	67
Nomenclature	EMDN	GMDN
Data base structure	6 different modules	Stand alone, exclusively for UDI

Get help from UDI registration experts

The differences outlined here are not comprehensive, but they aim to provide a general overview. Special attention should be paid to the file formats of the databases, the differences of possible product attributes, and the EU’s Basic UDI-DI.

Given their scope, implementing these various regulations can seem daunting at first. It may therefore be advisable to seek the assistance of an external UDI software service provider, such as tracekey, to support the company in implementing them correctly. This helps to avoid problems such as incorrect data or complicated upload procedures right from the start. The mytracekey UDI Manager supports medical device manufacturers with registration on EUDAMED, GUDID, AusUDID and swissdamed.

If you want to learn more about national MedTech regulations:

• MedTech in the UK
• MedTech in Saudi Arabia
• MedTech in Brazil
• Medical Device Registration in swissdamed

[Disclaimer]

The information provided here is only one possible interpretation of the regulations. These are also subject to constant change, so the information in this article may be incomplete or out of date. The above article is expressly not intended as legal advice. Please consult the official documents before making any business decisions. (Information status: September 2026)