MDR Classification Rules: Annex VIII Explained for Class I, IIa, IIb & III
Classification is the first step to CE marking. It decides whether you need a Notified Body, which conformity route applies and how much evidence your file must contain. We classify your device against all 22 Annex VIII rules and document the justification.
What is MDR classification?
MDR classification places your device in one of four risk classes, Class I, IIa, IIb or III, using the rules in Annex VIII of EU MDR 2017/745. The higher the potential risk to patients and users, the higher the class.
The class drives everything that follows: whether a Notified Body is involved, which Annex IX, X or XI route you take, the depth of clinical evidence and how often you report after certification. A wrong class means the wrong route, and that is one of the most common causes of delay.
EU MDR risk classes explained
Each class has its own conformity assessment route. Class I devices with a sterile, measuring or reusable surgical function need a Notified Body for those aspects only.
| Class | Risk | Example devices | Notified Body |
|---|---|---|---|
| Class I | Low | Bandages, stethoscopes, walking aids | No (self-declared) |
| Class Is / Im / Ir | Low | Sterile gauze, non-active clinical thermometers, reusable surgical forceps | For sterile, measuring or reuse aspects |
| Class IIa | Medium | Hearing aids, short-term urinary catheters, dental fillings | Yes |
| Class IIb | Medium to high | Infusion pumps, ventilators, bone fixation plates | Yes |
| Class III | High | Heart valves, breast implants, absorbable sutures, hip and knee replacements | Yes, with the deepest review |
The 22 MDR classification rules at a glance
Every device is checked against each rule group. If more than one rule applies, the highest class wins.
| Rules | Group | What they cover |
|---|---|---|
| Rules 1–4 | Non-invasive devices | Devices that touch intact skin or do not touch the patient, wound dressings, devices for channelling or storing blood and fluids, and devices that modify body fluids. |
| Rules 5–8 | Invasive devices | Devices entering body orifices, surgically invasive devices for transient, short-term or long-term use, and implantable devices. |
| Rules 9–13 | Active devices | Therapeutic and diagnostic active devices, software (Rule 11), devices administering medicines or energy, and other active devices. |
| Rules 14–22 | Special rules | Devices with medicinal substances, contraception, disinfection, X-ray image recording, animal or human tissues, nanomaterials, inhaled medicines, substance-based devices and closed-loop therapeutic devices. |
How we classify your device, step by step
A defensible classification that your Notified Body can accept without debate.
- 1
Define the intended purpose
FoundationWe pin down the medical purpose, patient group, user and body site, using your labels, IFU and claims.
- 2
Set duration & invasiveness
Annex VIII, Chapter IWe apply the MDR definitions for duration of use, invasiveness, implantable and active devices.
- 3
Apply every relevant rule
Rules 1–22We check each rule group, including the special rules, and take the highest class where several apply.
- 4
Check software & accessories
Rule 11 · MDCG 2019-11We classify standalone and embedded software and each accessory in its own right.
- 5
Write the classification rationale
Technical documentationWe document the rules applied and the reasoning, ready for your technical file and Notified Body review.
- 6
Confirm the conformity route
Next stepWe map the class to the right Annex IX, X or XI route and a realistic CE marking plan.
Common MDR classification mistakes
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MDR classification FAQs
How many classification rules are there under EU MDR?
There are 22 classification rules in Annex VIII of EU MDR 2017/745. Rules 1 to 4 cover non-invasive devices, 5 to 8 invasive devices, 9 to 13 active devices and 14 to 22 special rules such as nanomaterials, substance-based devices and devices with medicinal substances.
What happens if more than one classification rule applies?
If several rules apply to the same device, the strictest rule and the highest class apply. This is set out in the implementing rules of Annex VIII, Chapter II.
How is medical device software classified under MDR?
Software is classified under Rule 11. Software that provides information used for diagnostic or therapeutic decisions is Class IIa, rising to IIb if a wrong decision could cause serious deterioration of health or surgery, and Class III if it could cause death or irreversible deterioration. Software that monitors vital physiological parameters is IIb; most other software is Class I.
Did device classification change from MDD to MDR?
Yes. MDR added new rules for nanomaterials, substance-based devices and inhalation devices, a dedicated software rule, a new Class Ir for reusable surgical instruments and up-classified some devices. A device's MDD class cannot be assumed to carry over.
Who decides the class of a medical device?
The manufacturer classifies the device and justifies it in the technical documentation. The Notified Body checks the classification during its review. If they disagree, the matter goes to the competent authority under MDR Article 51(2).
Are accessories classified separately?
Yes. Accessories for a medical device are classified in their own right, separately from the device they are used with.
Not sure which class your device falls into?
Send us your intended purpose using the form below and we'll confirm its MDR class at no cost.
