UDI (Unique Device Identification): Complete Guide

What Is the UDI System?

The UDI system is a framework established by FDA to adequately identify medical devices sold in the United States from manufacturing through distribution to patient use. The system was mandated by the FDA Amendments Act of 2007 and implemented through a final rule published in 2013.

UDI improves patient safety by enabling more accurate reporting of adverse events, more efficient device recalls, better inventory management by healthcare facilities, and enhanced post-market surveillance. It also facilitates interoperability of device data across healthcare IT systems.

Three Core UDI Requirements

• Label/package UDI: Every device label and package must include the UDI in both human-readable (plain text) and machine-readable (barcode or RFID) formats
• GUDID submission: Device data associated with each DI must be submitted to FDA's GUDID before the device enters commercial distribution
• Direct marking: Devices intended to be used more than once and reprocessed must bear a permanent UDI directly on the device itself

UDI Structure: DI and PI Components

Every UDI consists of two components that together uniquely identify a specific device:

UDI Formats

The UDI can be encoded using any of the three FDA-accredited issuing agency formats:

• GS1: Uses GTIN (Global Trade Item Number) format — most common globally
• HIBCC: Uses the Health Industry Bar Code (HIBC) format — common in healthcare
• ICCBBA: Uses ISBT 128 format — primarily for blood, cells, tissues, and organs

GUDID: The Global UDI Database

The Global Unique Device Identification Database (GUDID) is FDA's publicly accessible database containing identifying information about medical devices that bear a UDI. Labelers must submit data to GUDID before a device bearing a new DI enters commercial distribution.

GUDID Data Elements

GUDID submissions can be made through the FDA GUDID web interface (manual entry) or via HL7 SPL electronic submissions for high-volume labelers. Use our UDI Lookup tool to search the GUDID database.

Labeler Codes and Issuing Agencies

Before you can create UDIs for your devices, you need a labeler code from an FDA-accredited issuing agency. The labeler is the entity whose name appears on the device label — typically the manufacturer or distributor.

Getting Started with UDI

Direct Part Marking Requirements

Devices that are intended to be used more than once and that are reprocessed before each use must bear a permanent UDI marking directly on the device itself. This requirement ensures traceability even when the original packaging is no longer present.

Marking Methods

• Laser etching: Most durable method for metal devices and surgical instruments
• Dot peen marking: Mechanical indentation suitable for metal surfaces
• Chemical etching: Uses acid or chemical processes for marking
• Inkjet printing: For non-metallic surfaces; must be validated for durability through reprocessing
• RFID tags: Can serve as the machine-readable UDI carrier for some device types

Validation Requirements

Direct marks must remain legible and scannable throughout the device's expected service life, including through repeated cleaning, sterilization, and use cycles. Manufacturers must validate that their chosen marking method can withstand the device's reprocessing conditions.

UDI Compliance Timeline and Exemptions

UDI requirements were phased in by device class, with Class III devices complying first. As of 2026, all device classes must comply with UDI labeling requirements:

• Class III (September 2014): Label/package UDI, GUDID submission
• Class III implantables (September 2015): Direct marking
• Class II (September 2016): Label/package UDI, GUDID submission
• Class II (September 2018): Direct marking
• Class I and unclassified (September 2022): Label/package UDI, GUDID submission

Exemptions and Exceptions

Certain devices and situations are exempt from some UDI requirements:

• Custom devices made under 21 CFR 812.3(b)
• Investigational devices used under IDE
• Devices distributed to a single facility and not commercially distributed
• Individual single-use devices distributed within a convenience kit

For device registration and listing, see our Device Registration Guide. For 510(k) submission guidance, visit our 510(k) Guide.