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Deciphering Medical Device Risk Classification Under EU MDR

The European Union Medical Device Regulation (EU MDR) represents a significant overhaul of the regulatory framework for medical devices in Europe. Among its key provisions is a revamped system for classifying medical devices. In this blog, we will delve into the intricacies of medical device classification under EU MDR and understand why it is a crucial step in the regulatory process.

Why Classification Matters

Medical devices come in a wide range of forms and functions, from simple bandages to complex implantable devices like pacemakers. To ensure a consistent and effective regulatory approach, it's essential to categorize these devices based on their level of risk to patients and users.

Accurate classification serves several critical purposes and is crucial for several reasons:

  • Compliance: Manufacturers must follow the appropriate conformity assessment route based on their device's risk class. Incorrect classification can lead to non-compliance and regulatory issues. Device classification helps manufacturers understand the regulatory pathway they need to follow for conformity assessment and compliance with EU MDR.

  • Patient Safety: The classification system ensures that higher-risk devices undergo more rigorous assessments and evaluations, enhancing patient safety. Proper classification helps regulators apply the appropriate level of oversight.

  • Market Access: Accurate classification facilitates the efficient placement of devices on the market, benefiting both manufacturers and patients.

  • Risk Management: By assigning devices to specific risk classes, regulatory authorities can tailor their oversight and requirements to match the inherent risks associated with those devices.

The Four Risk Classes

Under EU MDR, medical devices are divided into four risk classes, ranging from Low-risk Class I to High-risk Class III. The classification is primarily based on the device's intended use, the duration of contact with the human body, and the potential risks associated with its design and manufacturing. Here's a breakdown of the four risk classes:

Class I (Low Risk): Class I devices pose the lowest risk to patients and users. They include products such as bandages, thermometers, and non-invasive tools. Class I devices are typically non-sterile and do not have a measuring function.

  • Class Is (Sterile): Devices that need to be sterile, such as surgical gloves or sterile dressings, fall into this sub-classification.

  • Class Im (Measuring Function): Devices with measuring functions, such as blood pressure monitors, glucose meters, or thermometers, belong to Class Im.

  • Class Ir (Surgically Reusable): Reusable surgical instruments, like forceps and scissors, fall into Class Ir. These devices undergo a more rigorous assessment due to their potential for harm.

Class IIa (Low to Moderate Risk): Class IIa devices are still relatively low-risk but may have a more direct impact on a patient's health. Examples include hearing aids, contact lenses, and some diagnostic devices.

Class IIb (Moderate to High Risk): Class IIb devices fall into a higher risk category, encompassing devices like infusion pumps, surgical lasers, and long-term contact lenses. These devices may have a more significant impact on patient health, and they require more scrutiny.

Class III (High Risk): Class III devices are the highest risk category and include products like pacemakers, implantable defibrillators, and artificial heart valves. These devices are subject to the most stringent regulatory requirements and undergo rigorous assessments, including clinical evaluations.

Medical Devices Risk Classification Rules under Annex VIII of EU MDR

To determine the risk class of a medical device, manufacturers must refer to Annex VIII of EU MDR. This annex contains 22 classification rules, divided into four sections:

• Rules 1-4: Cover non-invasive devices.

• Rules 5-8: Cover invasive devices.

• Rules 9-13: Cover active devices.

• Rules 14-22: Special rules that apply to devices that don't fall into first three categories.

The classification rules take into account the intended purpose of the device and its duration of use. For example, if a device is intended for continuous use for more than 30 days, it may be classified differently from a device intended for short-term use.

Non-Invasive Devices

Non-invasive devices can fall into Class I, IIa, IIb or III depending on their contact with the skin or body fluids. The non-invasive devices which do not touch the skin or contact only the intact skin usually fall into Class I. Non-Invasive Devices that get in contact with injured Skin or Mucous Membrane are Class I when used for mechanical barrier, compression, or exudate absorption. They are Class IIa when used for managing the micro-environment of injured skin or mucous membrane and Class IIb when used for skin injuries breaching the dermis and healing by secondary intent.

The Non-Invasive Devices for Blood, Liquids, Cells, or Tissues are Class IIa if they may be connected to Class IIa, IIb, or III active device Or are for channelling or storing blood, body liquids, or tissues except for blood bags (blood bags are Class IIb). In all other cases, they are Class I devices.

The Non-Invasive Devices for Modifying Biological or Chemical Composition are Class IIb unless used for filtration, centrifugation, or exchanges of gas or heat, in which case they are Class IIa. The Non-Invasive Devices Involving Substances for In Vitro Use are Class III if they come into direct contact with human cells, tissues, organs, or embryos.

Invasive Devices

Invasive medical devices for body orifices, excluding surgically invasive ones, have specific classifications based on use and connection to active devices:

Non-Surgically Invasive Devices:

  • Class I for transient use.

  • Class IIa for short-term use, unless used in specific areas, in which case they're Class I.

  • Class IIb for long-term use, unless used in specific areas not absorbed by mucous membranes, then Class IIa.

  • If intended for connection to Class IIa, IIb, or III active devices, they are Class IIa.

Surgically Invasive Devices for Transient Use: Class IIa, except if they:

Specifically control, diagnose, monitor, or correct heart or central circulatory system defects (Class III).

Are reusable surgical instruments (Class I).

Are intended for direct contact with the heart, central circulatory system, or central nervous system (Class III).

Supply ionizing radiation (Class IIb).

Have a biological effect or are largely absorbed (Class IIb).

Administer medicinal products in a potentially hazardous manner (Class IIb).

Surgically Invasive Devices for Short-Term Use:Class IIa, unless they:

  • Specifically control, diagnose, monitor, or correct heart or central circulatory system defects (Class III).

  • Are intended for direct contact with the heart, central circulatory system, or central nervous system (Class III).

  • Supply ionizing radiation (Class IIb).

  • Have a biological effect or are largely absorbed (Class III).

  • Undergo chemical change in the body, except if placed in teeth (Class IIb).

  • Administer medicines (Class IIb).

Implantable and Long-Term Surgically Invasive Devices: Class IIb, except if they are placed in teeth (Class IIa) or are used in direct contact with the heart, central circulatory system, or central nervous system (Class III). If they have a biological effect or are largely absorbed (Class III).

  • Undergo chemical change in the body, except if placed in teeth (Class III).

  • Administer medicinal products (Class III).

  • Active implantable devices or accessories, breast implants or surgical meshes, total or partial joint replacements, except certain components,

  • Are spinal disc replacement implants or devices in contact with the spinal column, except certain components (Class III).

Active Devices

The classification of active medical devices is based on their intended use, the nature of the substances involved, and the potential risks they pose to the patient's health. Devices and software are categorized into Class I, IIa, IIb, or III accordingly.

The Active therapeutic devices that administer or exchange energy fall into Class IIa unless their pose a potentially hazardous risk to the human body. Factors considered include the nature, density, and site of energy application. Active devices intended for diagnosis and monitoring also are class IIa, except under specific conditions (e.g., supplying energy absorbed by the body, imaging radiopharmaceutical distribution, or direct diagnosis or monitoring of vital physiological processes). Software meant for providing diagnostic or therapeutic information is classified as Class IIa, unless it has the potential to cause severe harm or necessitate surgical intervention.

The Active therapeutic devices with characteristics that may pose a potentially hazardous risk to the human body fall into Class IIb. Devices that control, monitor, or directly influence the performance of active therapeutic Class IIb devices and active devices emitting ionizing radiation for therapeutic or diagnostic purposes and devices controlling or monitoring such radiation-emitting devices fall under Class IIb

Software intended for diagnostic or therapeutic purposes that have the potential to cause severe harm or require surgical intervention and the software intended for monitoring physiological processes with the potential to cause immediate danger to the patient also fall under Class IIb

Active devices intended for controlling, monitoring, or directly influencing the performance of active implantable devices fall under Class III. Software intended for providing information leading to decisions with an impact that may cause death or irreversible health deterioration also fall under Class III.

All other software and active devices that do not fall into the above categories are Class I devices.

Other Devices

  • Devices containing nano material with negligible, low and high / medium potential for internal exposure fall into Class IIa, IIb and III respectively.

  • Devices used for recording X-Ray Diagnostic images are Class IIa devices

  • Devices for contraception and prevention of STDs fall under Class IIb unless they are implanted or are invasive and intended for long-term use, in which they are Class III

  • Devices used for disinfecting and sterilizing medical devices are Class IIa where as those used on contact lenses and invasive devices are Class IIb.

  • Medical Device driven combination products are Class III devices

The medical device classification under EU MDR is a critical step in the regulatory process. It helps ensure that medical devices are appropriately assessed, regulated, and monitored, ultimately contributing to the safety and effectiveness of healthcare products used by millions of patients across Europe. Manufacturers must carefully navigate the classification rules to determine the risk class of their devices and ensure compliance with EU MDR's rigorous regulatory requirements.

If you have any further questions or need additional information about medical device classification or any other topic, feel free to ask. Your inquiries are important to us, and we're here to help!


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