FDA Issues Final Guidance on UDI Form and Content

By: Randolph Fillmore

July 14, 2021

Categories: AAMI News, Medical Device Manufacturers


The FDA has issued final guidance, Unique Device Identification System: Form and Content of the Unique Device Identifier (UDI) “to assist labelers and FDA-accredited issuing agencies in complying with unique device identifier (UDI) labeling requirements, including by clarifying FDA’s interpretation of certain requirements under 21 CFR 801.40.”

Under the FDA’s 2013 UDI Rule, each labeler must use one or more systems operated by an FDA-accredited issuing agency to assign UDIs that appear on device labels, on device packages, and, as applicable, on devices themselves as direct markings. Last year, the agency pushed back enforcement of compliance dates for Class I and unclassified devices, and certain devices requiring direct marking, until 2022.

“In order for there to be an effective identification system, it is essential that the FDA-accredited issuing agencies develop and operate systems for the assignment of UDIs that allow labelers using these systems to be in compliance with UDI labeling requirements,” the agency wrote in the final guidance.

The final guidance, which updates a 2016 draft guidance document, describes two forms of UDIs on the device label and device packages that must be presented:

  1. Easily readable plain text, described as providing a “human-legible” interpretation of the UDI data characters.
  2. Forms readable through Automatic Identification and Data Capture (AIDC) technology.

Some devices are required to be directly marked with the UDI, which may be through readable plain-text or AIDC technology (such as a bar code reader) or an alternative technology that will provide the UDI of the device “on demand.”

The FDA cautioned that if the labeler chooses the AIDC, the bar code form of the UDI should be tested for print quality. Also, UDI content must include a device identifier (DI) segment and a production identifier (PI) segment that conveys one or more of the identifiers.

“UDIs, particularly when provided through AIDC technology, are intended to allow rapid and accurate data acquisition, recording, and retrieval. The easily readable plain-text form allows healthcare professionals, patients, FDA, and other users of the UDI system to read and enter the UDI into data systems, such as patient records or reports to FDA, without technological assistance. Thus, the easily readable plain-text form may be used as an additional mechanism to capture the UDI if the AIDC form cannot be used,” the FDA wrote in the guidance document.  

The agency defined “data delimiters,” as a data character or set of data characters that identifies specific data elements within an encoded data string and represented in the UDI carrier, are key to UDI comprehensibility and utility. Data delimiters, used to identify the information that immediately follows them, vary based on the UDI system established by each FDA-accredited issuing agency.

The final guidance specified that the order in which the data is represented in easily readable plain text should be ordered to specify DI first and the PI, if there is one, second.

The guidance concludes by saying that stand-alone software has different labeling requirements, depending on whether it is distributed in package form.

The FDA is accepting comments on the final guidance at www.regulations.gov, docket number FDA-2016-D-1853.