Classification of medical devices under the EU MDR

Medical device classification is based on the intended purpose and risk of a device. The classification determines the level of complexity of the conformity assessment for CE-marking and has wide-ranging consequences for the regulatory requirements over the device’s entire lifecycle. If you are uncertain about what products are subject to medical device classification or you need to understand how to classify medical devices under the EU MDR, read on.
Before classifying your device, you should ensure that it qualifies as a medical device.

Replaces the version of 13.02.2024

Key takeaways:

• Medical device manufacturers should not assume that their existing classification under the former Directive 93/42/EEC (MDD) applies as is under the EU MDR. They should always verify the classification from scratch, per Annex VIII of the EU MDR

• All definitions, implementing rules and classification rules in EU MDR Annex VIII must be considered for the determination of the correct device class. Guidance documents MDCG 2021-24 as well as MDCG 2019-11, for medical device software, are essential resources to consider.

• Accessories for medical devices, Custom-made devices (CMDs), and “Annex XVI products” must be classified in their own right. So do medical devices manufactured and used within healthcare institutions. For “Annex XVI products”, additional rules apply.

Content:

What is medical device classification? What classes exist under the EU MDR?

Medical device classification is the action of identifying which device class applies to a given medical device, according to the classification rules in Annex VIII of Regulation (EU) No. 2017/745 on medical devices (EU MDR). 

The device class is one of the key elements that drive the level of scrutiny the device will be subject to, in particular:

• The need for a Notified Body in the conformity assessment process for CE-marking, and the extent of Notified Body involvement.
• The type and depth of the evidence of compliance, including clinical data, that the manufacturer must gather and maintain.
• The transitional periods granted to “legacy” devices, i.e. those still CE-marked under the former Directives (MDD, AIMDD).

Classification is incumbent on the manufacturer. However, in cases where a Notified Body needs to be involved in the conformity assessment process for CE-marking, there could be disagreement on the applicable class. Any resulting disputes between the manufacturer and its Notified Body must be referred for decision to the relevant competent authority. 

The EU MDR has maintained the division of devices into the same  4 class levels as in the former Directive 93/42/EEC on medical devices (MDD), but it has revisited some of the classification rules. See What classification changes have been introduced with the EU MDR? 

Those classes are established in increasing order of risk for patients and public health, namely:

• Class I – low risk, for example non-electronic walking aids.
• Class IIa – medium risk, for example orthodontic wires.
• Class IIb – medium-high risk, for example computer tomography devices.
• Class III – high risk, for example hip prostheses.

Class I is complemented with three sub-classes addressing specific features:

• Class Is – devices that are delivered sterile, for example sterile surgical gloves.
• Class Im – devices with a measuring function, for example, urine collection bag with graduated scale.
• Class Ir – surgical devices that are intended to be reprocessed.

How should manufacturers classify a medical device?

To classify the medical device, manufacturers need to consult Annex VIII of the EU MDR, which consists of three chapters: 

• DEFINITIONS SPECIFIC TO CLASSIFICATION RULES
• IMPLEMENTING RULES
• CLASSIFICATION RULES

The classification rules in Annex VIII of the EU MDR are divided into 4 subsections: 

• Non-invasive devices, 
• Invasive devices, i.e. those that penetrate the body, 
• Active devices, i.e. those that depend on a source of energy other than that generated by the human body and modify such energy, and 
• “Special” rules, which may apply to devices that already fall under any of the previous 3 categories, and therefore need to be always considered.

The first chapter of this Annex provides the relevant definitions required to apply the classification rules and the implementing rules. The definitions outline the device characteristics that are specific for the classification rules, such as:

• Categories of duration of use: Transient, short term, and long term;
• Definition of invasive versus non-invasive devices;
• Definition of active versus non-active devices

The below infographic summarizes the classification rules under the EU MDR:

The following steps should be followed: 

1. Evaluate each definition of both EU MDR Article 2 and Annex VIII chapter I, for applicability to the device in question.
2. Take all implementing rules in Annex VIII of the EU MDR into account. Implementing rules provide general guidance to the classification process. For example, if several rules or sub-rules apply, the strictest rule and sub-rule shall be applied.
3. Check all classification rules of chapter III Annex VIII, whether they are applicable to your medical device or not. As the intended purpose is the basis for applying the classification rules, it might be helpful to explicitly mention any limitations  (i.e. what the medical device is not intended to be used for). It is essential to be as precise as possible, a small difference of the wording can make a big difference from a regulatory viewpoint.

The extensive and useful guidance document MDCG 2021-24 discusses details on how to interpret and apply Annex VIII and also brings examples. It should always be used alongside Annex VIII when classifying a device.

What medical device classification changes have been introduced with the EU MDR?

There are no essential differences in the classification approach described in Article 51, but the EU MDR clarifies various aspects, such as: 

• New classification rules for several products e.g., medical device software, substance medical devices, nanomaterials.
• Clarification on the duration of “continuous use”.
• Explanation of when a device is considered to allow direct diagnosis.

In the European Union medical devices are classified according to their risk and divided into classes I, IIa, IIb and III.

As the former Directive 93/42/EEC on medical devices (MDD) did not take sufficient account of the degree of invasiveness and the potential toxicity of certain devices, in addition to Rule 11 for medical device software, the EU MDR added four new “special” rules:

• Rule 19 – Devices incorporating or consisting of nanomaterial

• Rule 20 – Invasive devices with respect to body orifices to administer medicinal products by inhalation

• Rule 21 – Substances or of combinations of substances that are intended to be introduced into the human body via a body orifice or applied to the skin and that are absorbed

• Rule 22 – Active therapeutic devices with an integrated or incorporated diagnostic function which significantly determines the patient management

Also, the former special Rule 18 for blood bags in the MDD was discontinued under the EU MDR as a separate rule, and is now part of Rule 2.

Some fine-tuning has been brought to other classification rules that already existed under the MDD, and the rule numbering has been affected. As such, manufacturers should not assume that their former MDD classification applies as is and should always verify the classification from scratch under the EU MDR.

What tips and special cases should manufacturers consider for medical device classification under the EU MDR?

Manufacturers must be aware that classification under the EU MDR also applies in the following cases:

• Accessories for medical devices, which should be carefully differentiated from components.
  For details, see How are accessories classified under the EU MDR?
• Medical device software (MDSW), including where such software is embedded in medical device hardware.
  For details, see How is medical device software (MDSW) classified under the EU MDR?
• Products without a medical intended purpose that are governed under the EU MDR, what is commonly referred to as “Annex XVI products”.
  For details, see How are “Annex XVI products” classified?
• Custom-made devices (CMD), even if they are not subject to CE-marking and only Class III CMDs require the involvement of a Notified Body, which is limited to the certification of the manufacturer’s Quality Management System. The same classification process as for non-CMDs should be followed by the manufacturer.
  

Moreover, healthcare institutions should also be aware that medical devices manufactured and used in-house, which benefit from certain exemptions according to EU MDR Art.5(5), also need to undergo classification.

Conversely, medical device classification does not apply to:

• Device part of a “Single integral product”, i.e. a non-reusable device-drug combination product intended exclusively for use in the given combination, which is governed by pharmaceutical legislation. 
• Procedure Packs or Systems, as they are merely assemblies of separately CE-marked devices.

The Medical Device Coordination Group (MDCG) has issued two guidance documents to help manufacturers with EU MDR classification: 

• MDCG 2021-24 Guidance on classification of medical devices.
• MDCG 2019-11 Qualification and classification of software – Regulation (EU) 2017/745 and Regulation (EU) 2017/746.

If these guidance documents do not suffice, the manufacturer can send an inquiry to the concerned competent authority (of the Member State where the manufacturer has its registered place of business) or, in the case of devices that require the involvement of a Notified Body in their conformity assessment process, the manufacturer can discuss the selected classification with its Notified Body.

Medical devices manufactured in healthcare institutions and used in-house, also need to undergo classification.

In case of a dispute between the manufacturer and its Notified Body, the competent authority will – after consulting the MDCG – decide on the classification and inform the MDCG and the commission about the decision. The competent authority will base its decision upon the classification rules given in Annex VIII of the EU MDR, new scientific evidence, and/or any information which becomes available in the course of the vigilance and market surveillance activities, as defined in Article 51 of the EU MDR.

Beware that there might be situations where the classification under the EU MDR  turns out to be convoluted, due to an incorrect qualification as medical device, which might be revealed through questions such as:

• Does my product qualify as a medical device?
• Is my device a medical device or an in-vitro diagnostic device?
• Is my product a medical device or a medicinal product?
• Delimitation to other regulated markets such as cosmetics, food or general consumer products.

To help with difficult qualification (but also classification) cases, the MDCG has issued and maintains a Manual on borderline and classification (current version 3 – September 2023), which manufacturers should consult in case of uncertainty. 

There is also the more specific MDCG 2022-5 guidance on borderline between medical devices and medicinal products under the EU MDR. 

To learn more about the qualification of medical devices and borderline issues, read our blog article Is my product a medical device in Europe? How to determine if your product requires medical device CE marking.

How are accessories classified under the EU MDR?

Per EU MDR Article 2(2) a medical device accessory is:

“an article which, whilst not being itself a medical device, is intended by its manufacturer to be used together with one or several particular medical device(s) to specifically enable the medical device(s) to be used in accordance with its/their intended purpose(s) or to specifically and directly assist the medical functionality of the medical device(s) in terms of its/their intended purpose(s).” 

Before classifying your device, it is important that you determine whether a given item that you consider an “accessory” to your main device falls under this legal definition. It is not always easy to clearly differentiate an accessory from a component.

Now, items intended specifically to replace a part or component of a device and that significantly change the performance, safety, or intended purpose of the device are considered to be a device, per Art. 23(2), and would be also subject to classification.

Accessories to medical devices are classified separately from the device (or “in their own right”, as implementing rule 3.2 states). This means that manufacturers of accessories must follow the same classification process as for medical devices.

How is medical device software (MDSW) classified under the EU MDR?

The EU MDR defines software as an “active device”, meaning that classification Rules 9 to 13 in Annex VIII that apply to active devices have to be considered. Among these, Rule 11 is specific to software. In addition, special Rules 15 and 22 can also apply to software.

Rules 9 to 12 are used to classify devices which are involved in the exchange of energy and/or substances between the body and active devices for diagnostic or therapeutic purposes. However, the risks related to medical “standalone” software mainly stem from incorrect or missing information, which can be indirectly harmful. To reflect this risk, Rule 11 was introduced.

The manufacturer is responsible for the correct classification of his medical device.

Classification Rule 11 states:

 “Software intended to provide information which is used to take decisions with diagnosis or therapeutic purposes is classified as class IIa, except if such decisions have an impact that may cause:

• death or an irreversible deterioration of a person’s state of health, in which case it is in class III; or
•  a serious deterioration of a person’s state of health or a surgical intervention, in which case it is classified as class IIb.

Software intended to monitor physiological processes is classified as class IIa, except if it is intended for monitoring of vital physiological parameters, where the nature of variations of those parameters is such that it could result in immediate danger to the patient, in which case it is classified as class IIb. 

All other software is classified as class I.”

Further clarification on the application of Rule 11 is given in guidance document MDCG 2019-11. This document focuses on the qualification and classification of medical device software and includes an informative table linking the EU MDR risk classification of software to the risk categorization framework developed by the IMDRF (International Medical Device Regulators Forum). The approach taken in the IMDRF publication (IMDRF/SaMD WG/N12FINAL:2014)  combines the significance of the information provided by the software to the healthcare decision (“treat or diagnose”, “drive clinical management” or “inform clinical management”) with the healthcare situation or patient condition (“critical”, “serious” or “non-serious”).

For more details, see our blog article on Medical device software (MDSW) under the EU MDR and IVDR.

How are “Annex XVI products” classified?

The EU MDR regulates not only medical devices, but also specific groups of similar products without an intended medical purpose. These groups are listed in Annex XVI, and thus commonly referred to as “Annex XVI products”. 

In general, Annex XVI products are classified in accordance with the classification rules in Annex VIII of the EU MDR. Accessories to Annex XVI products also fall under the EU MDR and, per Annex VIII Chapter II 3.2, they shall be classified in their own right. 

There are however some exceptions, documented in Regulation (EU) 2022/2347 on the reclassification of Annex XVI products that are considered to be active devices. These include the following “active devices”:

• High intensity electromagnetic radiation emitting equipment intended for the use on the human body for skin treatment is class IIb, unless it is intended for hair removal only in which case it is class IIa.
• Equipment intended to be used to reduce, remove or destroy adipose tissue is class IIb.
• Equipment intended for brain stimulation that apply electrical currents or magnetic or electromagnetic fields that penetrate the cranium to modify neuronal activity in the brain is class III.

Where should manufacturers document the classification rationale?

Annex II of the EU MDR on technical documentation specifies that the device description needs to include the device’s risk class and the justification for the classification rule applied (per section 1.1(f)).

It is good practice to present the justification in the form of a table, where all 22 classification rules in Annex VIII of the EU MDR are listed, and the justification for applicability or non-applicability is indicated for each of them. This shows to the Notified Body or competent authority who might review the documentation, that the manufacturer understands the classification process and has thoroughly applied it. In our consultancy practice, we recommend to do so even when the non-applicability is obvious, for example the non-invasive and invasive rules would never apply to medical device software.

How Decomplix can help

As you now know, the specifics and the intended use of a device are essential for the correct classification under the EU MDR. Are there specific questions you would like to discuss?

Are you wondering whether the risk classification under the EU MDR coincides with the risk classes in the USA?  Find more information in our bespoke article on Medical device regulatory strategy – US vs. EU.

We are happy to support you (re-)defining your intended purpose or classifying your medical device under the EU MDR, and pointing out the relevant differences from a US classification. Learn more about our services.

Further reading

• Is my product a medical device in Europe? How to determine if your product requires medical device CE marking
• The intended purpose – or what does your medical device do?
• Annex XVI and EU MDR – Guide to regulation of products without intended medical purpose
• Medical device software (MDSW) under the EU MDR and IVDR
• Risk Management for Medical Devices under EU MDR and ISO 14971
• Medical device regulatory strategy – US vs. EU
• Classification of in-vitro diagnostic medical devices under the IVDR
• Regulatory guide to Procedure Packs, Systems, IVD kits, and Configurable devices

This new version brings some clarification on the classification process and includes additional special cases beyond MDSW and Annex XVI products, e.g. Custom-made devices (CMDs), devices manufactured and used within healthcare institutions, or the device part in single integral combination products.