EU MDR Classification: Classes I, IIa, IIb & III
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Medical devices sold in the European Union are classified according to 22 rules laid out in Annex VIII of the MDR.
Video guide
EU MDR: Device Classification Rules
Learn how the 22 Annex VIII rules determine EU MDR device classes and how to apply the strictest relevant rule.
Open video pageTranscript (English)
Which MDR class is your device? The answer sets your route to the CE mark, and whether a notified body is involved. Four classes, twenty-two rules. Annex VIII of the MDR sets out 22 rules, grouped for non-invasive, invasive and active devices, including Rule 11 for software, plus special rules. If several rules apply to your device, the strictest one, giving the higher class, decides. Key inputs include the intended purpose, the duration of continuous use, how invasive the device is, and whether it is active. Transient means under 60 minutes; long term means over 30 days. And for legacy devices, the MDR class sets the deadline: December 31, 2027, for Class III and most implantable Class IIb devices, and December 31, 2028, for the rest. Start with three things. One: write the intended purpose first. Two: run every rule against it, and keep the strictest. Three: check MDCG 2021-24, revised in April 2026, for examples. Purpose first, then the rules. Pure Global covers registration, in-country representation, quality systems, audits and cybersecurity, in more than 30 markets. Visit pureglobal.com.
Background of EU MDR classification
New and legacy devices seeking regulatory compliance in the European Union (EU) need to confirm their classification under the Medical Devices Regulation 2017/745 (MDR) to determine the conformity assessment requirements. The MDR introduced four new classification rules that shifted conformity assessment requirements for devices already classified under the MDD. It also brought some products that were not previously regulated as medical devices under its scope, such as some products that do not have an explicit medical purpose but fit the risk profile of a medical device (e.g., some cosmetic and aesthetic devices listed in Annex XVI) and some software.
How medical devices are classified under the MDR
Classification is based on the intended purpose of the device, which articulates how the device functions, how the device should be used, and its clinical use scenario. You will classify your device according to the 22 rules laid out in Annex VIII of the MDR. The rules follow a risk-based logic based on the characteristics of the device, including its duration of contact with the body, degree of invasiveness, and whether it is active or non-active (i.e., does it require an energy source). Assess every applicable rule and implementing provision; the result must be justified against the intended purpose. If more than one rule is relevant to your device, the rule with the highest risk will apply. MDCG 2021-24 Guidance on classification of medical devices provides interpretations of the rules and how to apply them in practice.
Devices are classified into four tiers of increasing risk, though the lowest-risk tier has three sub-classifications:
Class I - low risk (e.g., wheelchairs)
- Class Is – sterile condition (e.g., surgical drapes)
- Class Im – measuring function (e.g., non-sterile thermometers)
- Class Ir – reusable surgical (e.g., certain surgical scalpels)
Class IIa - moderate risk (e.g., ultrasound devices)
Class IIb - high-moderate risk (e.g., ventilators, blood bags)
Class III - high risk (e.g., pacemakers, heart valves)
How classification affects regulatory requirements under the MDR
Classification dictates your conformity assessment route and the level of involvement by a Notified Body (NB), even if you have a legacy device. For high-risk devices, your NB can mandate resource-intensive conformity assessment requirements that can extend your timeline to market, such as pre-market clinical investigations or the need for expert panel review of your clinical data. Classification will also influence activities you must sustain throughout the life cycle of the device to remain on the EU market, such as your post-market surveillance and vigilance reporting requirements (including the types of reports, depth of information provided, and frequency) and supply chain or labeling traceability requirements. For legacy devices transitioning to the MDR, your final transition deadline is determined by your device’s classification under the MDR, not by the MDD.
Classification decision record
Record the intended purpose, contact duration, invasiveness, anatomical site, active function and applicable Annex VIII rules. Explain why competing rules apply or do not apply and use the strictest applicable result. Assess accessories separately. Software supplying information for diagnostic or therapeutic decisions requires a specific Rule 11 analysis; it is not automatically Class I because it has no patient contact.
| Result | Notified Body planning | Lifecycle link |
|---|---|---|
| Ordinary Class I | Generally self-declaration | PMS Report |
| Is, Im or Ir | Limited review of the relevant aspects | PMS Report and relevant controls |
| IIa, IIb or III | Applicable conformity assessment | Class-based PSUR and clinical evidence |
Examples help orientation but never replace the product's documented rule analysis.
Official framework and connected work
Use the current MDR, IVDR and Commission guidance for the applicable legal text and interpretation. Start from the EU market-entry hub for the overall pathway; this guide addresses the specific task within that program.
For regulatory terminology and the authority framework, see the EU MDR.
For software boundaries and Rule 11 context, see the SaMD and SiMD guide.
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Frequently asked questions
Unlike the classification scheme under the US FDA, the European concept is not based on substantial equivalence or use of predicates. Providing similarity or equivalence to a CE-marked device is not required to classify your device according to the MDR. However, similarity or equivalence can help justify the classification in your device’s Technical Documentation. There is also a formal requirement to reference in the Technical Documentation to previous and similar generations of the device and this shall include an overview of identified similar devices available on the EU or international markets, where such devices exist (MDR Annex II Section 1.2). In this context, ”similar” means that the devices have characteristics in common such as materials, design, function, intended use (refer also to MEDDEV 2.7.1 rev 4, Appendix A.1). Further, you may be able to leverage existing clinical data for a similar or equivalent devices as part of your clinical evaluation in lieu of clinical evidence.
Class I device manufacturers can self-declare the conformity of their devices by issuing the EU declaration of conformity, drawing up the Technical Documentation, and maintaining the basic quality management system (QMS) requirements, along with compliance with other applicable requirements (e.g., registration in EUDAMED ). Class I sterile, measuring, and reusable devices must meet the same requirements as Class I devices but also require NB review of their Technical Documentation as it relates to the sterilization, measuring, or reusable functions of the device, respectively. On satisfactory review, the NB will issue a CE Marking certificate.
Indications for use expand on the intended purpose to specify the applications for your device. They are part of the device description in your Technical Documentation according to Annex II Part 1.1 (c) and can include: “the intended patient population and medical conditions to be diagnosed, treated and/or monitored and other considerations such as patient selection criteria, indications, contra-indications, warnings [ . ] ” Your device’s indications for use should be considered carefully to ensure accurate classification of your device. For instance, devices intended for disinfecting and sterilizing medical devices are Class IIa under Rule 16 unless they are indicated for disinfecting invasive devices for end-point processing, in which case they are Class IIb.
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