By Martin Walter, Ph.D., CEO, Swiss MPC
Unique device identification (UDI) has been a hot topic in the industry since the FDA issued its final rule in 2013 requiring identification of devices through distribution and use. With the arrival of the European Medical Device Regulation (MDR) in 2017, the identification system expanded not only to another part of the world but also in terms of its requirements. While the basics have not changed significantly in the intervening years, medical device companies still struggle with management of UDI attributes and related issues. One topic that is frequently overlooked or put off is direct marking with UDI information.
Under both FDA 21 CFR Part 8011 (UDI final rule) and EU 2017/7452 (MDR), the UDI must be marked directly on reusable devices of all device classes. There are manifold direct marking technologies, including printing and engraving; however, laser marking is the most frequently used option, especially for reusable surgical instruments. While the FDA UDI final rule allows for a choice between automatic identification and data capture (AIDC) methods — like 2D barcodes and human readable interpretation (HRI), the MDR clarifies in Annex VI Part C 4.1 and 6.2.1 that both HRI and AIDC versions of the UDI are required to be directly marked on the device.
In addition, both the UDI final rule and the MDR make it clear that the UDI for any device type other than reusable devices shall be made available at the point of use. For example, the instructions for use of many trauma implants allow the resterilization of devices that are prepared and presented for surgery, as long as they remain unused. For these devices, there are a variety of options to convey the UDI at the point of use, like code-cards or RFID tags; however, the method of choice is often laser marking.
It should be noted that exemptions from the direct marking requirement (i.e., not technologically feasible/marking would interfere with the safety and performance of the device) are only applicable to reusable devices, as all other devices are not required to use a specific method to convey the UDI at the point of use.
With regard to timelines, the FDA has delayed its original deadlines for direct marking compliance for Class I and unclassified devices that are not implantable, life supporting, or life sustaining until no sooner than September 2022.3,4 The EU is requiring UDI attributes to be uploaded to the new European Database on Medical Devices (EUDAMED) within 18 months of the database’s launch, which is scheduled for May 2022.5 The schedule for requiring a UDI carrier to be affixed to the device itself under the MDR is May 2023 for Class III and implantable devices, May 2025 for Class IIa and IIb devices, and May 2027 for Class l devices.
The Challenge Of UDI Direct Marking
Direct marking of medical devices with UDI in any form is a design change that requires proper verification that the safety and performance of the device are not affected. While the addition of HRI information via laser marking is usually an easy process that can be rationalized in terms of safety based on existing markings on the device, adding 2D barcodes requires much more planning and verification.
As a first step, barcode sizes (e.g., 20x20 modules) need to be defined along with the size of the individual modules (a module is defined in GS1 general specifications as the narrowest nominal width unit of measure in a barcode6). The size must take into consideration the barcode’s readability with commercial scanners, marking accuracy, and the barcode’s required character string size. A good guideline is to stay around 0.25 mm per module, in order to guarantee readability with commercially available scanners and to avoid issues in marking placement on devices. For the specifications for barcodes, both FDA and MDR refer to the issuing entities of the device identifier (DI). For example, you will need to refer to GS1 general specifications6 whenever using GTINs (Global Trade Item Numbers).
Unfortunately, laser parameters used for clear text markings will likely be unsuitable to create a readable and durable 2D barcode. For this reason, the process of finding parameters that resist corrosion, do not impair mechanical strength of the bulk material, and support repeated cleaning and sterilization is time consuming. These criteria are important, especially when qualifying suppliers for marking of 2D barcodes. As even identical machines cannot usually run the same laser parameters for 2D barcode marking due to machine-specific degradation of the laser source, adjustment of laser parameters must be made for each individual laser marking machine and for each material and surface specification in use.
The individual part geometry has an additional influence on the readability of 2D barcodes, as surface curvature creates reflections that may impair the readability. Therefore, it is recommended to place 2D barcodes only on curved surfaces when the barcode height is less than 5 percent of the underlying curvature’s circumference.7
Two-dimensional barcodes cannot be read with the human eye, so verifiers are used to grade the quality of the marking and verify the content.8,9 These verifiers need to be implemented in production and quality control and also with any suppliers that perform 2D barcode marking on your devices. As most commercially available verifiers are designed to work on flat sample surfaces, companies might have to resort to custom-made verifiers to allow for efficient in-process quality controls of 2D barcodes.
In addition to the DI, 2D barcodes also need to contain a variable production identifier (PI), so every lot or serial number will require the generation of a new barcode at the laser marking station. Therefore, it is imperative to assure the availability of this information in digital form at any point during production.
The Benefits Of Direct Marking
Many companies consider UDI direct marking with 2D barcodes an unnecessary effort and try to work around it one way or another. In my opinion, however, it is advisable and desirable to implement this type of marking, especially for reusable surgical instruments. As more hospitals are tracking their instruments throughout their lifetimes and monitoring reprocessing cycles, it is evident that 2D barcodes would be a helpful tool for them and ultimately could be a selling point for medical device manufacturers. Especially when combined with serial numbers, hospitals could track how many times and on which patients a specific instrument has been used, thereby improving monitoring of reprocessing status, service needs, and instrument lifetimes.
Beyond the added benefit to customers, marking with UDI information increases device application safety through the information available in the FDA Global UDI Database (GUDID) and the EU’s EUDAMED. Direct marking also provides a safe and efficient way of fighting counterfeit devices.
Looking at the MDR compliance deadlines for UDI marking can be deceiving in the sense that the timelines feel long and comfortable at the moment. However, the intense knowledge buildup, planning, and supply chain preparation efforts necessary, along with internal procedure readiness and process changes, require a long lead time to successfully implement UDI direct marking. The task of supplier qualification alone can easily span two years from equipment acquisition to having validated laser parameters for all products in place. It is therefore wise to build a dedicated team early on and get started now.
- ISO / IEC TR 29158
- ISO / IEC 16022
- Department of the Navy IUDI Marking Guide, Sept. 2011
About the Author:
Martin Walter is CEO of Swiss MPC, a medical device and pharma industry consulting firm, based in Switzerland. He holds a Ph.D. in biomedical engineering and has been serving various multinational clients in the orthopedic implant, vascular intervention, and dental implant sector over the past decade. He has been working intensely with the new European Medical Device Regulation (MDR), all aspects of UDI, risk management, development, and quality and regulatory topics. You can reach him at firstname.lastname@example.org and connect with him on Linkedin.