FDA UDI: Labeler, DI/PI, GUDID & Direct-Marking Boundaries

Updated2026-07-14

Evidence map from FDA UDI labeler responsibility to label and package data, GUDID, and direct-marking conditions — BIO original evidence map. It separates labelers, issuing agencies, DI/PI presentation, GUDID's DI record, lifecycle changes and direct-marking boundaries. UDI/GUDID is not approval. Sources [1–7].

In short: Under FDA's UDI rule, the responsible party is the labeler. A UDI generally contains a mandatory, fixed DI and a conditional, variable PI, and is presented in easily readable text and AIDC form on labels and packages. The labeler submits device information to GUDID, but GUDID contains only the DI—not the PI—and does not identify who uses a device [1]. Some devices intended for more than one use and reprocessing before each use also fall within direct-marking requirements, subject to the applicable exceptions and alternatives [6–7].

Responsibility: identify the labeler first

FDA defines a labeler as the person who causes a label to be applied or modified with the intent that the device will be commercially distributed without later replacement or modification of that label. It is usually the manufacturer, but may be a specification developer, single-use-device reprocessor, convenience-kit assembler, repackager or relabeler. Adding only a distributor's name and contact details does not count as a label modification for this definition [1].

Labels and packages: DI is mandatory; PI is conditional

DI (device identifier): the mandatory, fixed portion identifying the labeler and a specific device version or model.
PI (production identifier): the conditional, variable portion; when present on the label it can include lot/batch, serial number, expiration date, manufacture date or a specified HCT/P code.
The labeler presents the UDI in easily readable plain text and machine-readable AIDC form [1].

GUDID: DI only—not PI

GUDID uses the DI as the key to basic device-identification information and does not contain PI. Public AccessGUDID also does not contain information about who uses a device [1]. A database record therefore is not a unit, lot or patient-use history; confirm regulatory status through the appropriate FDA records separately.

Issuing agencies and DI lifecycle control

A labeler develops its UDI under an FDA-accredited issuing agency system; FDA currently lists GS1, HIBCC and ICCBBA [3]. Under 21 CFR 830.50, each device version or model needs a DI, a change resulting in a new version or model requires a new DI, and a DI may not be reassigned to another version or model [5]. Packaging levels and editable GUDID fields require their own rule and guidance checks.

Direct marking: a conditional requirement

FDA's baseline trigger is a device that already must bear a UDI on its label, is intended for more than one use and is intended to be reprocessed before each use. Direct-marking exceptions and a route to request an alternative also exist, so the actual conclusion is product-specific [1,6–7]. UDI/GUDID supports identification and data records; it is not evidence that FDA cleared, approved or authorized the device [4].

Sources and reading limits

FDA UDI Basics: labeler, DI/PI, AIDC, GUDID and the baseline direct-marking trigger.
FDA GUDID Guidance: GUDID submission and maintenance.
FDA-accredited UDI issuing agencies: GS1, HIBCC and ICCBBA.
FDA clearance, approval and authorization check: regulatory status must be verified separately.
21 CFR 830.50: DI version/model and reassignment rules.
FDA Direct Marking Guidance: direct-marking requirements and terminology.
FDA UDI Exceptions and Alternatives: exception and alternative pathways.

The BIO angle

BIO supplies device materials, not finished-device UDI services. Grade, lot, CoA and change records can feed a device manufacturer's internal traceability and UDI data governance, but they do not replace labeler responsibility, GUDID submission or a finished-device compliance determination.

FAQ

What's the difference between DI and PI?

DI is the mandatory, fixed portion identifying the labeler and device version or model. PI is conditional and variable, and may represent lot, serial, expiration or manufacture-date information when included on the label.

Who files the UDI?

The 'labeler' — usually the manufacturer, possibly a specification developer, reprocessor, kit assembler or repackager/relabeler.

Does GUDID contain lot, serial or patient information?

No. FDA states that GUDID contains only DI, not PI; AccessGUDID also does not contain information about who uses a device.

What is direct marking?

Where the rule applies and no exception or alternative does, a device intended for more than one use and reprocessing before each use must bear a permanent UDI marking on the device itself. Check the product-specific conclusion against 21 CFR 801.45 and current FDA documents.

FDA UDI: labeler, DI/PI, GUDID and direct-marking boundaries