Unique Device Identifier (UDI)
The standard’s wording, as the sources below reproduce it:
“Indicates a carrier that contains Unique Device Identifier information.”
ISO 15223-1:2021, 5.7.10
What it means for you
Of the codes on the label, the one next to UDI is the official device identifier, which carries the product identifier and usually the lot or serial number and dates. Hospitals scan it to record which device a patient received.
Whether a device is right for you is a question for your pharmacist, nurse or doctor.
- What it looks like
- The letters UDI inside a rectangle, next to a barcode or 2-D data-matrix code.
- Where you see it
- Boxes and labels of devices sold in the EU and US, especially where several barcodes are printed.
- Other names
- UDI; UDI carrier; device barcode
What it does not tell you
The symbol does not decode the barcode for you, and the code is not a proof of authenticity on its own.
Often confused with
Indicates the manufacturer’s batch code so that the batch or lot can be identified.
More symbols in “Letters”
Sources
ISO 15223-1 is a paid standard, so the wording above is quoted as 3 publishers’ public documents reproduce it. Each was fetched and read on the date shown:
- Boston Scientific: Symbols Glossary — ISO 15223-1 5.7.10 “Unique Device Identifier — Indicates a carrier that contains Unique Device Identifier information.” Checked 2026-09-25.
- MedTech Europe: Use of Symbols to Indicate Compliance with the MDR, version 3.0 (November 2021) — Section 17 “Unique Device Identifier — MDR 2017/745 – Annex VI, Part C … 4.5. ‘When AIDC carriers other than the UDI carrier are part of the product labelling, the UDI carrier shall be readily identifiable.’” Annex I shows UDI in a box. Checked 2026-09-25.
- BÜHLMANN Laboratories: Symbol glossary, version 03 (release date 2025-02-04) — “Indicates a carrier that contains Unique Device Identifier information. This symbol may be used when multiple data carriers are present on the label. If used, this symbol shall be placed adjacent to the unique device identifier carrier.” Checked 2026-09-25.
Plain-language parts are in our own words; quotations are the sources’ wording.