The UDI Rule’s standardized identification system is intended to allow healthcare professionals, patients, FDA and other users to rapidly identify a medical device and key attributes regarding its safe and effective use.

On July 7, 2021, the U.S. Food and Drug Administration (FDA) issued a final guidance regarding the form and content of unique device identifier (UDI) labeling. The guidance will assist labelers of medical devices and FDA-accredited issuing agencies (who operate systems for issuing UDIs used by labelers) in meeting the requirements under 21 CFR Part 801, Subpart B, and the Unique Device Identification System Final Rule, 78 FR 58786 (September 24, 2013) (UDI Rule).

The UDI Rule’s standardized identification system is intended to allow healthcare professionals, patients, FDA and other users to rapidly identify a medical device and key attributes regarding its safe and effective use. Under the UDI Rule and 21 CFR 830.20, each labeler of a device must use a system operated by an FDA-accredited issuing agency to assign UDIs. To give labelers confidence in using those systems, the agencies must develop their systems to be consistent with legal requirements for UDI labeling. FDA’s newly issued final guidance is intended to facilitate these objectives by providing clarity regarding the existing legal requirements.

This guidance finalizes the July 25, 2016, draft guidance on this subject and applies to only UDI labeling, not universal product codes. In short, the guidance describes the two forms of a UDI, which are (1) easily readable plain text and (2) automatic identification and data capture (AIDC) technology; clarifies the content of the UDI, including the device identifier (DI) and production identifier (PI); and addresses the use of data delimiters that identify specific data elements within the UDI.

The label of every medical device must bear a UDI. The UDI is composed of a DI, which identifies the specific version or model of a device and the device’s labeler, and possibly a PI, which is a variable portion that identifies information such as the lot or batch number, serial number, expiration date, manufacture date or other identifiers set forth in 21 CFR 801.3. While the UDI Rule does not require listing any of the PI identifiers on the label, other regulations may require one or more PI identifiers to be on the label.

The UDI Rule requires that the UDI be presented in two forms: easily readable plain text and AIDC technology (except certain devices identified in 21 CFR 801.45 requiring direct marking). Plain text is human-legible text or text that can be interpreted by humans, while AIDC is read by a bar code scanner or other AIDC technology. AIDC conveys the UDI in a form that can be entered into an electronic patient record or other computer system automatically. The easily readable plain text of the UDI must include the DI and, if applicable, the PI, as well as any data delimiter(s) for the DI and PI.

Data delimiters are key because they distinguishing each specific element of a data string within a UDI. This allows users to parse the DI and PI in the plain text and verify that the AIDC information matches the plain text. Data delimiters also allow the UDI to be parsed into electronic systems after scanning with AIDC technology. If there are non-UDI elements like quantity included in the UDI, which the FDA does not require but may be inserted by the issuing agency’s system, the UDI should precede any non-UDI elements. Data delimiters work to distinguish the non-UDI elements as separate from the UDI.