DI, PI and the Pieces on the Label
A UDI has two parts. The device identifier (DI) is a fixed code for the specific device model and package level, issued under an FDA-accredited system such as GS1, HIBCC or ICCBBA. The production identifier (PI) varies by unit and may include lot or batch number, serial number, expiration date, manufacturing date and, for HCT/Ps, a distinct identification code.
The UDI must appear in both easily readable plain text and automatic identification form, such as a GS1-128 or DataMatrix barcode, with application identifiers like (01) for GTIN, (10) for lot, (17) for expiration and (21) for serial. Your label software must encode the PI from real production data, not from typed entries.
Where Contract Manufacturers Get UDI Wrong
Errors are rarely about the standard. They come from process gaps around label data and approval.
- Lot number typed manually onto a label instead of pulled from the work order
- Using a label template at a superseded revision
- Expiration date calculated incorrectly from manufacture date and shelf life
- Barcode not verified for readability or grade before release
- Label reconciliation not done, leaving extra labels from a prior lot on the line
- Package-level DI confused with the unit-of-use DI
Making the ERP Own the Label Data
The safest design pulls the DI from a controlled item master field, and pulls lot, serial and dates from the work order at print time, with the label template under document control and tied to a revision. Store the GTIN for each packaging level, the label revision, and shelf-life rules as attributes on the item. Record the printed label images or data string in the DHR, reconcile the count of labels issued, used and destroyed, and require a second-person or automated barcode verification before release.
If your ERP cannot print compliant labels directly, use a label tool that reads from the ERP and validate that interface.
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Direct Marking and Part-Level Identification
Some devices, such as reusable surgical instruments and certain implants, must carry the UDI as a permanent mark on the device itself when intended to be used more than once and reprocessed. That makes laser marking or dot-peen marking part of your validated processes, including mark legibility after cleaning, passivation and sterilization cycles. Verify the mark with a 2D code reader and record the grade.
The marking program, fonts, data matrix size and position all come from the OEM drawing, and any change is a controlled change under your quality system and, usually, a re-validation trigger.
When You Should Not Be the Label Owner
If your customer owns the labeler role, resist taking on GUDID submission or DI assignment unless it is a priced, contracted service with clear responsibility. Taking over a data submission task informally creates liability without control over the product description and regulatory status. A good compromise is to hold the OEM's label specification as a controlled document, build checks that your printed output matches it, and escalate any mismatch to the OEM before shipping.
Keep the quality agreement clear on who approves label content and who handles corrections.
Frequently asked questions
Is the contract manufacturer responsible for UDI?
Usually the OEM, as labeler, owns the DI assignment and GUDID submission, while the contract manufacturer applies the label to specification. Responsibilities depend on the contract, so define them in the quality agreement. Regardless, you are responsible for correct production identifiers and label control on your floor.
What is the difference between DI and PI in UDI?
The DI identifies the device model and package level and is fixed. The PI identifies production details for the unit, such as lot, serial number, expiration date and manufacturing date. Both appear in the UDI on the label in plain text and machine-readable form.
Do contract manufacturers need a GUDID account?
Only if they are the labeler for the device. If the OEM is the labeler, the OEM submits data to GUDID. Confirm roles in writing, because a contract manufacturer that also distributes under its own label takes on labeler duties.
Netray can add an AI check on label data against the OEM's specification and your work order before print, so a mismatched lot or expiration date is caught at the line, with the logic shown.