1. What Is UDI and What Does the FDA Require?

UDI Structure

A UDI consists of two parts:

• Device Identifier (DI): A fixed code identifying the device’s version/model (assigned by an FDA-accredited issuing agency like GS1 or HIBCC)
• Production Identifier (PI): Variable information such as lot/batch number, serial number, manufacturing date, or expiration date

FDA UDI Direct Marking Rule

Under 21 CFR 801.45, the FDA requires that reusable devices that are reprocessed between uses must bear a permanent UDI directly on the device itself — not just on the packaging.

Key definitions:

• “Reprocessed” means the device undergoes high-level disinfection or sterilization between each use
• “Permanent” means the mark must remain readable throughout the device’s intended lifetime
• The UDI must be in both human-readable and machine-readable (AIDC) formats — typically a 2D DataMatrix code

Exceptions:

• Direct marking would interfere with device safety or effectiveness
• Technically infeasible due to device size or design
• The manufacturer must document why the exception applies

EU MDR Equivalent

The EU Medical Device Regulation (MDR) Article 27 requires similar direct marking on reusable devices. Implementation deadlines extend through 2027. If you sell in both markets, plan for dual compliance.