The United States Food and Drug Administration (“FDA”) has published a guidance on Unique Device Identification System (“Guidance”) to explain the standards for Unique Device Identifiers(“UDI”) and the FDA's suggestions for their form and content to ensure that UDIs created under systems for the issuance of UDIs satisfy the goals of the Unique Device Identification System Final Rule (“UDI Rule”).

The Guidance discusses the use of data delimiters and the order in which data should be presented in the UDI carrier's easily readable plain-text form, while provides a description of the two forms of a UDI, which include the easily readable plain-text form and the automatic identification and data capture (“AIDC”) technology form. Additionally, the Guidance is intended to help labelers and FDA-accredited issuing agencies in complying with UDI labeling requirements, including by clarifying FDA’s interpretation of certain requirements under 21 CFR 801.40.

FDA established that the UDI Rule requires the label and device package of every medical device to bear a UDI, unless an exception or alternative applies. Additionally, some devices are required to bear a permanent marking providing the UDI on the device itself if the device is intended to be used more than once and intended to be reprocessed before each use. Further, under the UDI Rule, there are specific labeling requirements for stand-alone software regulated as a device.

As per the Guidance, It is stated that a UDI consists of a device identifier (“DI”) and a production identifier (“PI”).Under 21 CFR 801.3, while “unique device identifier” is defined as “an identifier that adequately identifies a device through its distribution and use by meeting the requirements of [21 CFR 830.20]” , “device identifier” is defined as “a mandatory, fixed portion of a UDI that identifies the specific version or model of a device and the labeler of that device”.

While 21 CFR 801.3  defines “Labeler” as "(1) any person who causes a label to be applied to a device with the intent that the device will be commercially distributed without any intended subsequent replacement or modification of the label; and (2) any person who causes the label of a device to be replaced or modified with the intent that the device will be commercially distributed without any subsequent replacement or modification of the label, except that the addition of the name of, and contact information for, a person who distributes the device, without making any other changes to the label, is not a modification for the purposes of determining whether a person is a labeler." , 21 CFR 830.3 defines “Issuing agency” as an organization accredited by FDA to operate a system for the issuance of unique device identifiers.

Additionally, according to 21 CFR 801.3, a "production identifier" is "a conditional, changeable component of a UDI that identifies one or more of the following when placed on the device's label: (i) The lot or batch within which a device was manufactured;(ii) The serial number of a specific device;(iii) The expiration date of a specific device;(iv) The date a specific device was manufactured; (v) For an HCT/P regulated as a device, the distinct identification code required by 21 CFR 1271.290(c) of this chapter.”

Unique Device Identifier

The UDI Rule stipulates that the UDI on the device label and package must be shown in both plain-text and AIDC technology formats. In addition, as per the 21 CFR 801.45, certain devices must be directly marked. Further, for those certain devices, the UDI may be directly marked on the device itself, using one or both easily readable plain-text or AIDC technologies, or any other technology that provides the device's UDI on demand.

The FDA has declared that UDIs are intended to allow rapid and accurate data collection, recording and access, particularly when provided through AIDC technology. In this regard, it is also stated that if the AIDC form is not available, the easily readable plain text form can be used as an additional mechanism to capture the UDI. Further, the FDA defines “easily readable plain-text” as human-legible interpretation of the UDI data characters.

Under the 21 CFR 801.3, AIDC is defined as any technology that conveys the UDI or the DI portion of a UDI of a device in a form that can be entered into an electronic patient record or other computer system via an automated process. The Guidance states that the AIDC form of the UDI must be in a format that can be read by a barcode scanner or other AIDC technology, it is emphasized that the labeler must ensure that the AIDC form of the UDI can be reliably read at points where it is important to capture device identification information during distribution and use. The Guidance also states that labelers should refer to the FDA-approved issuing agency's guidelines to determine which AIDC formats are supported by the issuing agency's UDI system.

For the purposes of this guide, the FDA has defined "UDI carrier" as a method of communicating UDI and potentially non-UDI elements utilizing easily accessible plain text and/or AIDC formats. The FDA mentions in the Guidance, that UDI carriers could contain non-UDI information about the device. The FDA also stated that in the Guidance, under 21 CFR 801.40(b), the easily readable plain-text and AIDC forms of a UDI must include: (1) a device identifier segment; and (2) a production identifier segment that conveys one or more of the identifiers enumerated in the definition of a “production identifier” at 21 CFR 801.3 when included on the device label. However, the FDA has emphasized that the device descriptor section and the production descriptor section cannot contain data delimiters for non-UDI items or non-UDI items. Further, the FDA noted that while the UDI Rule does not require any of the five identifiers containing a PI to be on the label, other regulations may require one or more of the identifiers containing a PI to be on the label.

Moreover, for the purposes of this guide, the FDA defines "data delimiter" as a defined data character or set of data characters that identifies individual data elements within an encoded data string represented in the UDI carrier. The FDA also mentions in the Guidance, that data delimiters are used to identify the data that comes after them, and they differ depending on the UDI system established by each FDA-accredited issuing agency.

FDA further explains that the data delimiters allow the UDI to be distinguished and captured separately from any non-UDI elements that may be represented in the UDI carrier. Moreover, if non-UDI elements are included in the UDI carrier, separate data delimiters for these non-UDI elements should be included. Without appropriate data delimiters to identify non-UDI elements, individuals may not be able to use the easily readable plain-text form of the UDI to identify a device and computer systems may not be able to capture accurately the UDI in AIDC form via an automated process.

Additionally, the FDA has specified that in the easily readable plain text format of the UDI carrier, the UDI must precede non-UDI elements, and that the easily readable plain text format of the UDI must be ordered to indicate DI first, followed by PI when it is applicable. Also, according to the Guidance, if there are non-UDI elements in the UDI carrier, the non-UDI elements should follow the PI that is part of the UDI in an easily readable plain text format.

Lastly, FDA emphasizes that there are different labeling requirements under 21 CFR 801.50 for stand-alone software depending on whether or not it is distributed in packaged form. FDA advises that for stand-alone software that is not distributed in packaged form, UDI labeling requirements are met if the UDI is provided through an easily readable plain-text statement displayed whenever the software is started and/or an easily readable plain-text statement displayed through a menu command. In such cases, the PI must also convey the stand-alone software’s version number.

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