New unique device identification labeling rules are on the way for medical devices, so it’s best for engineers to be aware of what impact they may have prior to them being mandatory. This article looks at the main points behind the coming rule and the considerations for ensuring proper symbol quality and label/mark verification.

Figure 1: UDI label example using GS1 formatThe unique device identification (UDI) program is an initiative from the U.S. FDA. The goal is to improve the nation’s health by standardizing the marking on medical devices so that all of those involved in their production, distribution, stocking, and use can readily identify the device in question and get reliable access to critical data concerning its use and history.

While it might seem that compliance will be as easy as a simple barcode placed on a box, it’s actually a bit more complicated. Some medical devices, such as heart valves and stents, tend to change their identity as they move through the supply chain. They may start with a manufacturer’s part number, be re-branded for a particular market, get re-numbered by a distributor, and then receive a new stock number when they arrive in a hospital stock room.

The aim of the UDI program is to provide a permanent unique ID for each device, which will also be indexed into a database containing the critical data for each device. The rationale is that this will allow efficient recalls and adverse event tracking, deter counterfeits, and promote accuracy of patient records.

Figure 2: Machine vision software verifies and ensures a match between GS1-formatted symbols and human readable text.Key Points
Published in July 2012, the proposal includes an implementation time table for standardized device and package labeling, and product registration for Class III devices (which are critical for life support) within one year of the final publication. The proposed time table requires permanent marking of implantable devices within two years of publication.

The FDA requires that automatic identification and data capture (AIDC or Auto ID) technology be used to mark a device’s package with a UDI via a 1D or 2D symbol or some other Auto ID technology, such as RFID. This information is referred to as the device identifier. The UDI program, however, does not require a specific type of Auto ID technology but does specify that 1D or 2D symbols be accompanied by human readable text. In addition, the UDI program does not require serialization but does require that 1D or 2D symbols contain the serial number and expiration date if these are marked elsewhere on the package. This data is referred to as the production identifier. The program specifies that the UDI, and if present, production identifier, are formatted using one of a small number of established standards, such as those provided by GS1 and HIBCC (Health Industry Bar Code Council).

Figure 3: Machine vision software with verification capability can also grade the quality of a printed or marked symbol.The UDI for a given manufacturer’s product/model/package will be issued and registered by a small number of non-profit agencies such as GS1 and HIBCC. In the case of GS1, this will be based on the GS1 Global Trade Identification Number (GTIN), which can be thought of as a grown-up version of the UPC codes that can be seen at the supermarket. The UDI will be added to a database, along with a defined set of product attributes (master data), such as version and model information, and any clinically important information, such as sterilization requirements and latex content.

Label Verification
There are two challenges that normally accompany any new labeling requirement using Auto ID technology: verifying the format of the encoded information against the application requirement and checking that the mark or code meets quality requirements to allow easy reading at the point of use.

Content Verification
It is expected that many labelers will opt for the GS1 format that uses application identifiers to specify the meaning of contents of a 1D or 2D symbol. In the example of a hypothetical minimal UDI label (Figure 1), the application identifiers (01), (10), and (17) identify the product ID (Global Trade Identification Number), lot number, and expiration date.

Figure 4: Examples of 2D Data Matrix symbols directly marked on medical devices.Labelers will need simple systems to check that 1D or 2D symbols are properly formatted, and that the contents are correct and match the human readable text. Machine vision software programs are becoming available that allow even novice users to check and separate the fields within a GS1-formatted symbol, read the human readable text, and verify that the form and content of both is correct.

Symbol Quality and Grading
Printed or directly marked symbols that are low contrast, blurred, or partially obscured can be very challenging to decode. Symbols must be produced at the highest level of quality available in order to be reliably decoded with the wide range of barcode readers and cameras in use. High quality 1D and 2D symbols can be validated through verification at the time of printing or marking (Figure 2), and grading according to the appropriate industry standard (Figure 3). ISO standards 15415 and 15416 specify a methodology for grading printed 2D and 1D symbols respectively. Labelers should always use symbols graded C or higher to ensure compliance with industry standards and dependable decoding throughout the supply chain. A third standard, AIM-DPM-2006, is typically used to grade symbols that have been marked directly onto a device (also known as direct part marks).

Direct Part Marking Requirements
The UDI program states that all devices that will be implanted or sterilized and reused must have permanent marks (Figure 4). In most cases, this will require use of direct part marking techniques, such as laser marking, laser bonding, or dot peen, to make a mark directly on the surface of the part. The challenging nature of creating these marks means that quality monitoring at the point of application is even more important. In-line monitoring of marking processes can be achieved with machine vision software that includes robust verification options.

More Information
Be ready to create, validate, and verify labels that meet and exceed the upcoming UDI program regulations. Read more information and view the progress of the UDI proposal at the FDA’s website.

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