Classification of medical devices
The Medical Device Regulation (EU) 2017/745 (MDR) introduces a detailed classification system for medical devices, based on the level of risk posed to patients and users. The classification determines the appropriate conformity assessment procedure and the involvement of a Notified Body.
Risk Classes
Medical devices are divided into four main risk classes:
- Class I: Low risk
- Class IIa: Medium risk
- Class IIb: High risk
- Class III: Very high risk
Class I also includes the following subcategories:
- Is: Devices supplied in a sterile condition
- Im: Devices with a measuring function
- Ir: Reusable surgical instruments
Classification Rules
The MDR outlines 22 classification rules, grouped into four categories:
- Non-invasive devices: Rules 1–4
- Invasive devices: Rules 5–8
- Active devices: Rules 9–13
- Special rules: Rules 14–22
The complete list of classification rules can be found in Annex VIII of the MDR.
Implementation Rules
Annex VIII also includes implementation rules to support the correct application of the classification system. Key points include:
- If multiple rules apply, the highest risk class prevails.
- Software is classified based on its intended purpose and associated risks.
- Accessories are classified separately from the device they support.
Devices without a Medical Purpose
The MDR also applies to specific products without a medical purpose, as listed in Annex XVI. These products are classified using the same rules as medical devices (Annex VIII).
Practical Application
- Accurate classification requires:
- A clear definition of the intended purpose
- Evaluation of all relevant classification rules
- Justification of the selected classification in the technical documentation