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MDR Classification Criteria: Class I, IIa, IIb, III
Under the MDR, medical devices are categorized into four risk classes based on their intended use and associated risks. The classification rules consider criteria that encompass invasiveness, duration of use, and potential harm to patients or users and determines a risk class. Here's a breakdown of each class:
Class I: This group includes low-risk devices like non-invasive devices, such as hospital beds or bandages, or invasive tools used only transiently in body orifices, such as dental impression materials. Class I devices can be active, such as examination lamps.
For many Class I devices, the declaration of conformity does not require third party assessment by a notified body. Examples include medical gloves and tongue depressors.
However, the MDCG 2021-24 Guidance on the classification of medical devices specifies three subclasses of Class I devices that do require third-party assessment by a Notified Body:
- Class Ir (Reusable Surgical Instruments): These devices (instruments) are intended to be used multiple times after appropriate procedures for cleaning and sterilization. A notified body is required to assess aspects relating to the reuse of the device, in particular cleaning, disinfection, sterilization, maintenance and functional testing and the related instructions for use. Forceps or scalpels are an example of this subclass
- Class Is (Devices placed on the market in a sterile condition): These devices are sold and delivered in sterile condition. A notified body is required to assess the aspects relating to establishing, securing and maintaining the sterile condition. An Example would be sterile bandage or a sterile syringe.
- Class Im (Devices with a measuring function): Any Class I device with a measuring function must provide accurate measurement results. A notified body is required to assess aspects relating to the metrological requirements. Examples include expansion thermometers and measuring cups.
Class IIa: Devices of this category pose a medium risk, for example, short term corrective contact lenses, feeding pumps, and polymer film wound dressings. For devices of class IIa, a conformity assessment conducted by a notified body will ensure they meet all regulatory criteria. This procedure includes the assessment of a technical documentation, including a clinical evaluation assessment, which are described later in this article.
Class IIb: Devices of the class IIb pose a higher risk then Class IIa, so more data and analysis is required to demonstrate their performance and safety. As a result, the notified body conformity assessment procedure takes longer and, by the nature of the device, can involve more experts, including clinical experts. Typical examples for this class are devices that are used for longer time periods, such as long-term corrective contact lenses and urinary catheters, devices with critical functions, such as lung ventilators or infusion pumps, and devices that emit radiation, such as therapeutic X-ray sources.
Class III: Such Devices are the highest-risk devices and include life-sustaining implants and medication delivery systems. Examples include are heart valves, pacemakers, or drug-eluting stents. Class III must meet the strictest regulatory requirements to ensure patients and users are as safe as possible.
In addition to requiring more evidence for initial certification, the MDR requirements related to post market surveillance, risk management and clinical evaluations increase with the risk classification.
The risk class determines the requirements for clinical evaluation, Periodic Safety Update Report (PSUR), and Summary of Safety and Clinical Performance (SSCP), ensuring thorough monitoring and safety assessment of these devices. In addition to the risk class above, other characteristics of the medical device and its intended use can impact the regulatory requirements. These include energy sources and whether the devices are implanted.
Active and Implantable Devices
Active devices: Devices that depend on a source of energy, other than that generated by the human body for that purpose of gravity. Active devices have specific risks related to the conversion of energy that are considered in the classification of the device. Errors in classification can be made where a non-active devices that act as energy conduits without modifying the energy, including some electrodes or fibre-optic devices, are classified as active and active devices based on manually tensioned springs or elastomeric pumps are mis-classified as non-active as there is no electrical power source. The EU MDR also considers devices using prestored gases and/or vacuums as active; however, not all regulatory authorities hold the same opinion.
Implantable devices: Implantable devices require special consideration in regulatory processes due to their surgically invasive placement and longer-term use in the body. Additional requirements include the supply of an implant card and information to the patient. Implantable devices can occur in Class IIa, IIb and III.
Regulatory Requirements
The classification of medical devices under MDR influences the regulatory requirements and obligations that manufacturers, authorized representatives, and importers must comply with:
Conformity Assessment
As mentioned above, whereas Class I devices, manufacturers can self-assess conformity to the requirements. On the other hand, devices in Class Ir, Im, Is, IIa, IIb, and III require third party conformity assessment by a Notified Body to confirm that the manufacturer’s declaration of conformity complies with the MDR requirements. The conformity assessment considers the results of testing according to applicable standards to the device to generate objective evidence that proves that the device meets applicable safety and performance requirements. The manufacturer also presents clinical data integrated into post-market surveillance and risk management to demonstrate a positive benefit-risk ratio for the patients and users. Where requirements are met, the manufacturer can make a legally-binding declaration of conformity and place CE marking on their devices.
Technical Documentation
The data for conformity assessment includes technical documentation. This obligatory and essential tool includes, but is not limited to, a detailed description of the device's design, the materials used, the intended purpose, results of performed tests, biocompatibility, clinical evaluation and market surveillance. Technical documentation is required whether the manufacturer self-declares a Class I device or instructs a notified body to perform conformity assessment.
Manufacturers must make available up-to-date technical documentation to the EU Competent Authorities to assess the safety and performance of the device. For manufacturers located outside the EU, this documentation must be lodged with and retained by their Authorised Representative.
Clinical Evaluation and Post-Market Surveillance
Clinical evaluation and post-market surveillance is required for all medical devices, regardless of risk classification, although the requirements increase with increasing risk class. The clinical evaluation presents evidence and conclusions that demonstrate the safety and performance of the medical devices. Post-market surveillance systems are required for all devices to monitor real-world performance, gather user feedback, and document adverse events. All devices other than Class I devices need follow-up studies and Periodic Safety Update Reports (PSURs); the level of data required and frequency of these reports increases with the risk class.
Instructions and labels
Medical device manufacturers must meet specific labelling requirements defined in the MDR and including basic information such as product specifications, intended purpose, important precautions, and any contraindications or warnings that helps users understand how to use the device safely and effectively, thereby reducing the risk of misuse and potential accidents.
Special Rules for borderline products
The EU Commission's borderline document outlines additional provisions for products that may fall between regulatory categories or that have unique characteristics requiring special consideration.
The borderline document helps manufacturers determine the appropriate classification and regulatory pathway for products that may not fit neatly into the standard categories. This includes products with dual purposes, those incorporating medicinal substances, and innovative technologies that present new challenges in classification.
For more detailed information, manufacturers can refer to the Commission's Borderline Document, which offers specific guidance and examples to aid in the classification process. Understanding and applying these special rules ensures that all medical devices, including exceptional products, meet the necessary safety and performance standards, thereby facilitating market access and regulatory compliance.
Supporting Links:
- Detailed information about the classification according to the VO (EU) 2017/745 MDR can be found in Annex VIII: EUR-Lex - 02017R0745-20230320 - EN - EUR-Lex (europa.eu)
- Official guidance on classification is available in the MDCG Paper 2021-24: mdcg_2021-24_en_0.pdf (europa.eu)
CE Marking under Regulation MDR (EU) 2017/745
Do you have questions about obtaining CE Marking in Europe for your medical device under Regulation MDR (EU) 2017/745? Reach out to us for more information and assistance.
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Dr. Murugan Kandasamy
A strong business leader with people and process focus, with about 3 decades of experience spanning across manufacturing, telecom, IT, Consulting and Certification industries.
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