Medical device classification under the MDR is not just a regulatory checklist item.
It’s actually an important regulatory decision that influences medical device’s clinical, commercialisation and compliance strategies.
I’m going to provide answers to 10 questions that can help understand medical device classification under the MDR better.
1. What does medical device classification under the MDR mean?
Simply put, medical devices are classified into specific classes based on their risk to patients and other users. The classification should consider each device’s intended purpose, duration of use and invasiveness.
Device classifications are conducted using classification rules. The rules are provided by the medical devices regulation (MDR). You can find the classification rules in MDR Annex VIII.
There are four risk classes under the MDR. They are from lowest to highest:
- Class I (with subclasses Is (sterile condition); Im (measuring function); and Ir (reusable surgical))
- Class IIa
- Class IIb
- Class III
The higher the risk class, the higher the risk level of the device.
Devices with a higher risk class are subject to stricter rules (and evaluation with greater scrutiny) than lower risk devices.
2. What is the impact of medical device classification?
Sets the conformity assessment route. Device risk class determines which conformity assessment route applies to a device. It also defines whether conformity needs to be assessed by an external party, a notified body.
Guides clinical evaluation and clinical investigations. The higher the risk class, the higher the level of clinical evidence you need to present of the device in the clinical evaluation. Clinical investigation requirements are stricter for higher risk class devices.
Influences post-market surveillance activities. Some of the post-market surveillance (PMS) documentation requirements are based on the device risk class. The classification also affects the level you need to aim for in the device’s PMS activities.
Shapes traceability requirements. Device risk class has an effect on the traceability requirements concerning a device. These requirements focus mostly on the UDI and Eudamed registrations.
Affects the information supplied with the device. Under certain conditions, devices in the lower risk classes may be provided to users without the instructions for use.
3. Who is responsible for medical device classification?
Manufacturers are responsible for classifying their medical devices under the MDR. The MDR requires manufacturers to include the classification decision and justification in the device’s technical documentation.
However, notified bodies and competent authorities have the right to review and challenge the assigned classification.
4. How to classify medical device software (MDSW)?
When classifying software, which drives a device or influences the use of a device, it must be classified in the same class as the device.
If the software is independent of any other device, it needs to be classified in its own right.
Software’s classification does not depend on its location (e.g. is it embedded, operating on a platform, on the computer/mobile phone/cloud, etc.).
Regarding modular software, modules which qualify as medical devices under the MDR, are subject to individual risk classification. When classifying modular software, it’s important to clearly define each module’s boundaries and interdependencies.
For further details on classifying software under the MDR, I recommend checking out MDCG 2019-11 Guidance on Qualification and Classification of Software in Regulation (EU) 2017/745 – MDR and Regulation (EU) 2017/746 – IVDR.
5. How do AI Act classification and MDR classification affect each other?
As a general rule, the AI Act does not have an effect on the risk classification of a medical device artificial intelligence (MDAI) under the MDR.
However, the classification of a medical device under the MDR determines whether the AI system qualifies as high risk under the AI Act.
An MDAI is a high-risk AI system under the AI Act, if the MDAI is a safety component, or the AI system is itself a medical device, AND the MDAI is subject to a third-party conformity assessment by a notified body according to the MDR.
For more details on the connection between AI Act and MDR, I suggest looking into AIB 2025-1 MIB 2025-6 Interplay between the Medical Devices Regulation (MDR) & In vitro Diagnostic Medical Devices Regulation (IVDR) and the Artificial Intelligence Act (AIA).
6. What factors to consider when classifying custom-made devices?
MDCG 2021-3 Questions and Answers on Custom-Made Devices tells us that the following factors need to be taken into account when classifying custom-made devices:
- the intended medical purpose of the final custom-made device (CMD), adaptable medical device or patient-matched medical device;
- whether it is an implantable medical device (i.e. whether the part, component or material is intended to be used in the manufacturing of an implantable CMD, adaptable medical device or patient-matched medical device);
- the risks related to the intended contact or interaction of the product as a part, component or material in the final CMD, adaptable medical device or patient-matched medical device with the patient’s body.
7. Does risk class impact the time needed for notified body audit and technical documentation assessment?
According to Team-NB Code of Conduct, device risk class is one of the factors, which affect how long audits and technical documentation assessments take.
Team-NB gives the following estimates:
Audits
- If audit scope includes class III devices: At least +10% increase in audit duration
- If audit scope includes only low-risk products (class IIa and less): Maximum -15% decrease in audit duration
Technical documentation assessments (first round)
- If device is Class Is, with technical documentation aspects reviewed per Article 52(7): +0.5-4 days *greater if large range of diverse devices are covered.
- If device is Class Ir, with technical documentation aspects reviewed per Article 52(7): +0.5-1 day.
- If device is Class Im, with technical documentation aspects reviewed per Article 52(7): +0.5-1 day.
8. Why might a medical device risk class go up?
Changes in intended purpose or indications. Higher risk class may be triggered, if for example the invasiveness of the device or duration of use increases. Broader indications and more critical impact on patients’ health can lead to a higher risk class too.
Changes in regulatory requirements in the current market. Regulators update regulations from time to time to keep up with developments in the sector. Replacing EU directives with two regulations MDR and IVDR is a prime example. The MDR introduced new classification rules. As a result, many previously low-risk devices, such as software, needed to be classified into higher risk classes.
Device enters a new market. Device classifications are not identical across global markets. Even if the device stayed the same, it may need to be classified differently in different markets. An example of highly variable classifications is NaOCl solutions used for root canal treatments. Their classifications can be anything from non‐classified to high risk, according to an article.
Interested to read more about classification changes and recommended next steps?
Take a look at my earlier blog posts here and here.
9. How to manage medical device classification over time?
It’s likely that during the life cycle of your device, there will be changes in your company, the requirements or the device itself. You need to manage the changes, including the impact they might have on your device classification.
Quick tips:
- Maintain a change management system within your quality management system (QMS)
- Keep an eye on post-market phase changes and additions
- Stay informed of regulatory changes
- Keep regulatory strategy up to date
- When an update is triggered, be ready to adapt.
10. What are the main steps in classifying a device?
Determine if the MDR applies to the device. Familiarise yourself with the definition of a medical device, accessory for a medical device, and the list of products without an intended medical purpose under the MDR. Compare them to your device’s intended purpose.
Establish the intended purpose. Review the device claims. Determine the device’s medical purpose, target population, and conditions of use.
Apply the classification rules. Identify all rules. If multiple rules apply, the strictest rule and sub-rule resulting in higher classification will apply.
Document the classification and its rationale. Manufacturers must document the classification decision and supporting rationale in the technical documentation.
This article attempted to answer key questions about medical device classification under the MDR, which manufacturers and others working with medical devices might be asking.
If you have any questions, please contact me.
