Unique Device Identifier (UDI)

The European UDI consists of three building blocks:

• The Device Identifier (DI), which is a static item identification code.
• The Production Identifier (PI), which is a set of variable data that ensures product traceability (e.g. a batch number, a serial number, an expiry date).
• The Basic UDI-DI, which is the model number of a medical device group.

The MDR stipulates that the Device Identifier (DI) and the Production Identifier (PI) are applied directly or indirectly to each product or each packaging unit in plain text and encrypted in a machine-readable barcode, 2D code or RFID chip.

In addition, the manufacturer must store the relevant product information in the European UDI Database, which is part of the European Database for Medical Devices (EUDAMED).

The Basic UDI-DI is a key element in the entire European UDI system. The manufacturer must include it in the declaration of conformity and in the technical documentation of the respective device. This way, the corresponding information or master data of the product can be called up at any time in the supply chain.

The MDR came into force on May 25, 2017 with regard to both medical devices and in vitro diagnostic medical devices. However, medical devices can still be certified under previous law during a three-year transitional period.

Starting May 26, 2021, the MDR requires manufacturers to present an EC certificate when placing medical devices on the European market for the first time. For in vitro diagnostic medical devices, the start date is May 26, 2022. However, the implementation of the certificate will happen gradually. In this sense, the obligation to present an EC certificate for medical devices with class I to III will only be completed in 2025, while for in vitro diagnostic medical devices the year of completion will be 2027.

In order to accomplish the requirements of the MDR, manufacturers must assign a UDI to each of their products and store the product information in the EUDAMED database. In principle, assigning the UDI can be done via a label or direct marketing. The exception is reusable medical devices (e.g. surgical instruments), for which a UDI must be directly applied on the product.

It is important to note that certain products are subject to special provisions and transitional periods in accordance with article 120 of the MDR.

Medical devices are divided into several classes. The potential health risk for humans is determinant for the classification. In this sense, products with the lowest hazard potential are assigned to class I while products with the highest risk are assigned to class III. Class II, in its turn, is subdivided into class IIa and class IIb. In vitro diagnostic medical devices are divided into groups A, B, C and D.

In the USA, a database assigns a class to a product. In the event that a product cannot be found in this database, class 3 automatically applies until the FDA downgrades it if necessary. In Europe, however, the class assigned to a certain product is based on the following criteria:

• How long does the medical treatment take?
• Where does the treatment take place? What is the degree of invasiveness?
• Is the product applied to the central circulatory system, heart or central nervous system?
• Is the product a reusable surgical instrument?
• Is the product an active therapeutic or diagnostic medical device?
• Does the product contain biological material from animals or humans?

Examples of product classes for medical devices (without claiming to be complete):

Examples of product groups for in-vitro diagnostic medical devices (without claiming to be complete):

Various technologies are available in the labeling industry for the implementation of the MDR: ink, laser and labels. In order to find out which labeling system is suitable for the respective application, the following questions must be clarified in advance:

• Is the medical device that is going to be marked a reusable device (e.g. a surgical instrument)?
• What material is the medical device made of?
• Is the surface of the device straight or curved?
• What are the line speeds within production?
• What information must be provided in addition to the UDI code?
• How is the production environment (e.g. dusty, damp, particularly cold or warm)?

It is important to note that, aside from traditional labeling systems, the industry has developed special labeling solutions for medical devices and in vitro diagnostic devices.

Surgical instruments are reusable medical devices. As a result, the usage of labels for UDI marking is not an option. Instead, the UDI must be directly applied on the product surface using a direct marking system. At the same time, the marking must be permanent and even withstand chemical cleaning cycles and autoclaving.

Since medical instruments and implants are usually made of titanium or stainless steel (the latter are sometimes also made of plastic), lasers are the preferred solution to mark the UDI. It is worth noting that laser marking systems are able to mark various materials, including plastic, metal, ceramics or even coated cardboard, in a quick, contact-free and precise way. A major advantage of laser marking is that it is permanently abrasion-resistant and can withstand any cleaning or sterilization process.

The following three laser marking processes are used in the medical technology sector:

• Engraving: in this case, part of the material melts or evaporates due to the high heat generated by the laser. This creates a clearly tactile marking on the material surface, which is why it is used wherever deep penetration into the material is required.
• Occasion marking: in contrast to engraving, occasion marking is gentle on the material. It is often used to mark reusable medical instruments, implants and surgical utensils made of titanium and stainless steel. The materials used in these cases react when exposed to oxygen and heat, with the upper layers of the material oxidizing and discoloring.
• Color change: this marking process produces a color change in numerous plastics used in medical technology.

Both occasion marking and the color change neither wear away nor throw up any material. This prevents germs and bacteria from settling. Another advantage of laser marking: it is corrosion-free and biocompatible.

The MDR stipulates that both medical devices and their outer packaging must be marked with a UDI.

Typical packaging materials for medical devices are plastic film, cardboard or Tyvek®. Plastic or film packaging has a non-absorbent surface. Inkjet printers with quick-drying ink are able to mark such materials legibly and durably. There is a wide range of inks for these applications. In addition, inkjet printers are easy to use and stand for high system availability.

If flexible film packaging needs to be marked, this can be done with thermal transfer printers. Thermal transfer printing is a cheap alternative to labels.

Materials such as absorbent cardboard boxes or Tyvek® (a non-woven fabric made from polyethylene), can be marked with thermal inkjet printers.

Sterile packaging in the medical sector is often made of Tyvek®. This material has special properties: it consists of millions of vapor-permeable microfibers that form a smooth surface. In order to mark this material, the ink must adhere well to the surface and not go through the permeable fibers to the packaged product. Thermal inkjet printers in connection with quick-drying inks print such materials in high resolution and durably. In conjunction with inks such as the HP 2590, the thermal inkjet printers of the Markoprint series from Weber Marking Systems apply information such as the UDI to such packaging in an MDR-compliant manner. The print quality is excellent because the ink cartridge is at the same time the print head. This means that replacing the cartridge implies replacing the print head.

In addition to direct labeling systems, label printing systems can be used at all packaging levels - primary, secondary and tertiary. They automatically print all the necessary information on a label and apply it to the product or packaging. With the Legi-Air series labeling machines from Weber Marking Systems, different dispensing stamps are available to attach the labels to the product.

Instead of a normal label, the products can also be marked with RFID labels. These labels are particularly useful when information has to be read at a distance or in bulk. RFID labels can also store more information than traditional labels or store it in several languages.

The Legi-Air 4050 is a label printer and dispenser that prints and applies RFID labels fully automatically. The integrated RFID print module prints and programs RFID labels with all the necessary information. A bad tag reject which automatically sorts out any faulty or non-readable RFID labels is also available.

The GS1 is an organization that develops and promotes the implementation of identification, communication and process standards. The GS1 is also involved in the implementation of the Medical Devices Regulation. GS1 Germany, for example, is accredited by the EU Commission as a UDI allocation body. In fact, manufacturers of medical devices and in-vitro diagnostic devices who implement the UDI using GS1 standards are able to meet both the regulatory requirements in the USA and Europe.

GS1 standards offer multiple advantages when it comes to implementing the UDI. These advantages include identification, marking and data exchange.

With regard to identification, the MDR provides three essential building blocks for the clear identification of medical devices and in vitro diagnostics devices:

• The UDI Device Identifier (UDI-DI).
• The UDI Production Identifier (UDI-PI).
• The Basic UDI (UDI-DI).

The GS1 provides standards that enable UDI-compliant identification of medical devices and in vitro diagnostic devices. These are:

• The Global Trade Item Number (GTIN), which can be used as a UDI ID.
• The GS1 data identifier, which can be used as a UDI-PI.
• The Global Model Number (GMN), which can be used as a base UDI-DI. Within the framework of the GS1 standards, the GMN is used to identify the model of a product from which the trade item is derived.

Regarding labeling, the UDI requires all information on the UDI-DI and UDI-PI to be attached to the packaging or to the product itself. In order to achieve this, the GS1 offers several solutions, including:

• The GS1-128 barcode.
• The GS1 data matrix code.
• RFID labels.

In terms of data exchange, manufacturers are obliged to transmit the master data of their products to the European UDI database. Here, the GS1 recommends that manufacturers make the data available to all users via the Global Data Synchronization Network (GDSN).

For the practical implementation of the GS1 standards and process recommendations, the GS1 has created a GS1 Solution Partner platform. Companies from a wide range of sectors are brought together to advise manufacturers of medical and in vitro diagnostic devices on the implementation of the UDI using GS1 standards and offer suitable solutions.

Weber Marking Systems is a GS1 Solution Partner for the labeling of medical devices and in vitro diagnostic devices. Our company is a full-service provider of labeling solutions - from laser marking and inkjet printers to labeling systems. Our labeling experts know the requirements of the Medical Devices Regulation and are very familiar with the GS1 standards. Weber Marking Systems has tested various labeling processes on materials such as paper, foil and metal and knows which solution is suitable for the various medical devices and their packaging. Our solutions guarantee a durable, abrasion-resistant (even permanent in the case of surgical instruments) and very legible marking.

As a manufacturer of medical and/or in vitro diagnostic devices, you should first check which deadlines apply to your products. Institutions such as the GS1 support and advise you on how to identify and label your products in a UDI-compliant manner.

Even if longer transitional periods apply to your products, you should start taking care of the implementation of the UDI now because the capacities of the solution providers are limited. In addition, it may be that production systems have to be adapted - especially if new labeling technology has to be integrated. This requires early planning so that you can bring your products to the market in a timely manner and in a UDI-compliant manner.

As a GS1 Solution Provider, Weber Marking Systems will be happy to advise you on the best way to mark your products in a UDI-compliant manner.