What is UDI and Why Does it Exist?

UDI (Unique Device Identification) is a system for assigning a unique numeric or alphanumeric code to every medical device and its packaging. The UDI system enables traceability throughout the supply chain — from manufacturer to hospital to patient — and is the infrastructure enabling rapid, precise device recalls, adverse event tracking, and post-market surveillance. When a device is associated with a serious adverse event, UDI allows regulators and health systems to identify every patient who received that specific device or lot.

UDI Structure: DI and PI

Every UDI has two components: the Device Identifier (UDI-DI), which identifies the specific device model and is fixed for a given device version, and the Production Identifier (UDI-PI), which identifies the specific production unit and includes the lot or batch number, serial number (for serialised devices), manufacturing date, and expiry date as applicable. The UDI-DI is registered in a public database (EUDAMED in the EU, GUDID in the USA). The UDI appears on device labels in both human-readable interpretation (HRI) and machine-readable data carrier (barcode or 2D matrix) formats.

EU MDR UDI Deadlines by Device Class

EU MDR UDI requirements have been phasing in by device class: Class III devices — UDI required since May 2021; Class IIa and Class IIb devices — UDI required since May 2023; Class I devices — UDI required from May 2025. Systems and procedure packs have specific deadlines. All UDI data must eventually be submitted to EUDAMED. Turkish manufacturers exporting Class I devices who have not yet implemented UDI are already beyond the compliance deadline.

Choosing a UDI Issuing Agency

Manufacturers must obtain their UDI-DI codes from an EU-accredited UDI Issuing Agency. The three recognised agencies are: GS1 (using GS1 standards — the most widely used globally, including the GS1 GTIN for the UDI-DI and Application Identifiers for the UDI-PI), HIBCC (using the Health Industry Business Communications Council system, common in the US), and ICCBBA (for blood, cellular therapy, and tissue products). For Turkish manufacturers selling in both EU and USA markets, GS1-based UDIs are typically the most practical choice as GS1 is recognised by both EUDAMED and the FDA's GUDID.

EUDAMED Registration

EUDAMED (European Database on Medical Devices) is the EU's central database for medical device information and is the destination for EU UDI data. Manufacturers must first register as an actor in EUDAMED, then register their devices with UDI data. EUDAMED registration is mandatory for all CE-marked devices. Turkish manufacturers who are not yet registered as actors in EUDAMED should begin this process immediately — the registration itself requires an active CE Mark and a valid Notified Body relationship for Class I+ devices.

Label Implementation Requirements

UDI must appear on device labels in human-readable form and as a machine-readable data carrier. For standard devices, a linear barcode (GS1-128) or 2D data matrix (GS1 DataMatrix) is used depending on label space. For very small devices or those where labelling space is limited, the MDCG provides guidance on alternatives. Direct Part Marking (DPM) — permanently marking the UDI directly on the device — is required for implantable Class III devices. Label redesign, print validation, and barcode quality verification are practical implementation steps that require production planning.

UDI Implementation Checklist for Turkish Manufacturers

Complete the following before your next regulatory audit: ☑ GS1 membership obtained and GLN (Global Location Number) registered ☑ UDI-DI codes generated for all current device versions and configurations ☑ Labels redesigned to include UDI in HRI and machine-readable format ☑ Barcode quality verified per ISO/IEC 15415 or 15416 ☑ UDI data registered in EUDAMED (EU) and/or GUDID (FDA) ☑ ERP/MES system updated to capture and record UDI-PI (lot, serial, expiry) at production ☑ Distribution records updated to include UDI traceability ☑ Quality management system updated with UDI procedures

Conclusion

UDI implementation is one of the most practically complex MDR compliance requirements but also one of the most operationally valuable — once in place, it enables traceability, recall management, and post-market surveillance in ways that were previously very difficult. Turkish manufacturers should treat UDI as an infrastructure investment in their quality system, not simply a regulatory burden.