MDD to MDR Classification: EU MDR Medical Device Classification Rules
The transition from the Medical Devices Directive (MDD) 93/42/EEC and Active Implantable Medical Devices Directive (AIMDD) 90/385/EEC to the EU Medical Device Regulation (MDR) 2017/745 introduced important changes for medical device manufacturers selling products in the European Union.
One of the key areas affected is medical device classification. While the MDR continues to use four main risk classes – Class I, Class IIa, Class IIb and Class III – the classification rules have been expanded and revised. These changes can result in some devices being classified at a higher risk level than under the MDD.
The classification of a medical device determines the applicable conformity assessment procedure, clinical and technical documentation requirements, involvement of a Notified Body, and ultimately the pathway toward CE marking under the EU MDR.
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What Is Medical Device Classification Under the EU MDR?
Under EU MDR Article 51, medical devices are classified according to their intended purpose and inherent risks. The detailed classification criteria are provided in Annex VIII of Regulation (EU) 2017/745.
Classification is based on factors such as:
- How long the device is intended to be used
- Whether the device is invasive
- Whether it is surgically invasive or implantable
- Whether it is active or non-active
- The anatomical location where it is used
- Whether it administers or removes substances
- Whether it incorporates medicinal substances
- Whether the device has a diagnostic or monitoring function
- The potential risks associated with its intended purpose
Manufacturers must establish the classification based on the device’s intended purpose, not simply on its technical characteristics.
MDD vs MDR Medical Device Classification
The basic four-class structure remains, but the MDR introduced new or modified rules that can affect classification.
| Classification | General risk level | Examples |
|---|---|---|
| Class I | Lowest risk | Certain non-invasive devices |
| Class IIa | Moderate risk | Certain monitoring and invasive devices |
| Class IIb | Higher risk | Certain long-term invasive or active devices |
| Class III | Highest risk | Certain implantable and high-risk devices |
There are also specific Class I subcategories, including Class I sterile, Class I measuring, and Class I reusable surgical instruments.
A device previously classified as Class I under the MDD may therefore require reassessment under the MDR. If the device moves to Class IIa, IIb or III, the manufacturer’s conformity assessment requirements may become more demanding.
Key Changes From MDD to MDR Classification
The transition from MDD to MDR introduced several important changes.
1. More Detailed Classification Rules
The MDR contains 22 classification rules in Annex VIII, compared with the classification framework under the previous directives.
The rules cover non-invasive devices, invasive devices, active devices, implantable devices, devices incorporating medicinal substances, software, devices using human or animal tissues, and substance-based devices.
2. Software Classification Has Changed
One significant development is Rule 11, which addresses software intended to provide information used for diagnostic or therapeutic decisions.
Depending on factors such as the importance of the information provided and the potential impact of a decision on a patient, software may be classified as Class I, IIa, IIb or III.
This means software manufacturers should not automatically assume that standalone medical software is Class I.
Learn more about CE marking for software as a medical device.
3. Implantable and Surgically Invasive Devices
Rule 8 covers surgically invasive devices intended for long-term use and implantable devices.
Certain implantable devices are subject to Class III classification because of their higher potential risk to patients. Manufacturers of implantable devices should therefore carefully assess duration of use, implantability, anatomical location and intended purpose.
4. Substance-Based Devices
The MDR introduced Rule 21, which applies to certain devices consisting of substances or combinations of substances that are introduced into the body through a body orifice or applied to the skin and are absorbed or locally dispersed.
Some products that may previously have been considered lower risk can therefore require a different classification under the MDR.
5. Active Therapeutic Devices With Diagnostic Functions
Rule 22 applies to certain active therapeutic devices with an integrated or incorporated diagnostic function that significantly determines patient management.
Such devices may be classified as Class III, reflecting the potential impact of their diagnostic function on treatment decisions.
EU MDR Classification Rules in Annex VIII
The EU MDR classification rules are divided into several groups.
Non-Invasive Devices
- Rule 1: Non-invasive devices
- Rule 2: Devices for channeling or storing substances
- Rule 3: Devices modifying the biological or chemical composition of substances
- Rule 4: Devices in contact with injured skin or mucous membrane
Invasive Devices
- Rule 5: Invasive devices related to body orifices
- Rule 6: Surgically invasive devices for transient use
- Rule 7: Surgically invasive devices for short-term use
- Rule 8: Surgically invasive and implantable devices for long-term use
Active Devices
- Rule 9: Active therapeutic devices
- Rule 10: Active diagnostic and monitoring devices
- Rule 11: Medical device software providing information for diagnostic or therapeutic decisions
- Rule 12: Active devices intended to administer or remove substances
- Rule 13: Other active devices
Special Classification Rules
- Rule 14: Devices incorporating a medicinal substance
- Rule 15: Devices used for contraception or prevention of sexually transmitted diseases
- Rule 16: Devices intended for cleaning, disinfection or sterilization
- Rule 17: Devices specifically intended for recording diagnostic images generated by X-ray radiation
- Rule 18: Devices using non-viable tissues or cells of human or animal origin
- Rule 19: Devices incorporating or consisting of nanomaterial
- Rule 20: Invasive devices related to body orifices used to administer medicinal products by inhalation
- Rule 21: Substance-based devices introduced through a body orifice or applied to the skin and absorbed
- Rule 22: Active therapeutic devices with an integrated diagnostic function
The applicable rule should always be determined based on the device’s intended purpose and characteristics.
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How Does MDR Classification Affect CE Marking?
Correct classification is an important starting point for the CE marking process for medical devices.
A manufacturer’s classification affects the conformity assessment procedure and whether a Notified Body needs to be involved.
For example, certain Class I devices may be eligible for conformity assessment without Notified Body involvement, subject to the applicable requirements. Higher-risk devices generally require greater regulatory scrutiny and Notified Body involvement.
Manufacturers should therefore complete classification before finalizing their regulatory strategy and technical documentation.
For more information, see our guide to CE marking for Class I, II and III medical devices.
How to Determine the Correct MDR Classification
Manufacturers can approach classification through the following steps:
- Define the intended purpose of the device.
- Identify whether the device is active, non-active, invasive or implantable.
- Determine the intended duration of use.
- Identify the applicable rule or combination of rules under MDR Annex VIII.
- Apply the relevant classification criteria.
- If more than one rule applies, use the rule that results in the higher classification where required by Annex VIII.
- Document the rationale for the classification.
- Determine the applicable conformity assessment procedure.
- Identify whether a Notified Body is required.
- Update the technical and clinical documentation accordingly.
Manufacturers should maintain a documented rationale because classification affects several other parts of the regulatory submission.
What Should Manufacturers Do When Moving From MDD to MDR?
Companies transitioning existing devices from MDD to MDR should conduct a structured regulatory gap assessment.
This can include reviewing:
- Device classification
- Intended purpose
- Technical documentation
- Clinical evaluation
- Risk management
- Post-market surveillance
- Labeling and instructions for use
- General Safety and Performance Requirements
- Quality management system
- Conformity assessment route
- Notified Body requirements
Manufacturers should also evaluate whether changes in classification create additional clinical, technical or quality requirements.
Our resources on EU MDR compliance and EU MDR technical documentation can help manufacturers understand these requirements.
How Operon Strategist Can Help With MDR Classification
Determining the correct EU MDR medical device classification can be challenging, particularly for manufacturers transitioning from MDD to MDR or launching new products in Europe.
Operon Strategist provides medical device regulatory consulting covering MDR classification, CE marking, technical documentation, clinical and regulatory strategy, quality management systems, and global product registration.
Our CE marking and EU MDR/IVDR services help medical device manufacturers understand applicable European regulatory requirements and prepare for market entry.
We can support manufacturers in reviewing their device classification, identifying regulatory gaps, preparing documentation, and developing an appropriate conformity assessment strategy.
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FAQ's
What are the medical device classes under the EU MDR?
The EU MDR classifies medical devices into Class I, Class IIa, Class IIb and Class III, based primarily on intended purpose and risk.
How many classification rules are there under EU MDR?
Annex VIII of EU MDR 2017/745 contains 22 classification rules, covering non-invasive, invasive, active, implantable and other specific types of medical devices.
Can a Class I device under MDD become Class IIa under MDR?
Yes. Changes to the classification rules can result in certain devices being assigned a higher risk class under the MDR.
Does medical device classification affect CE marking?
Yes. Classification influences the conformity assessment procedure, documentation requirements and whether a Notified Body must be involved.
Where are the EU MDR classification rules located?
The detailed medical device classification rules are provided in Annex VIII of Regulation (EU) 2017/745.