How to Classify Your Medical Devices Correctly

Under the EU Medical Device Regulation, medical devices fall into four classes: I, IIa, IIb and III, "taking into account the intended purpose of the devices and their inherent risks" (MDR Article 51(1)). You will also see classes IIa and IIb written as 2a and 2b. The class decides which conformity assessment route applies and whether a notified body has to be involved. Classification follows the rules in Annex VIII.

Start With the Intended Purpose

"Application of the classification rules shall be governed by the intended purpose of the devices" (Annex VIII, 3.1). The intended purpose is what the manufacturer states on the label, in the instructions for use, in promotional or sales materials and in the clinical evaluation (Article 2(12)). Define it first and check that your product is a medical device at all.

How Annex VIII Works

Annex VIII has 22 rules in four groups:

Duration of use is one of the factors, defined in Annex VIII, 1.1 to 1.3: transient means normally intended for continuous use for less than 60 minutes, short term between 60 minutes and 30 days, long term more than 30 days. These are not classes: a short-term device can end up in different classes depending on the rule.

If several rules, or several sub-rules within one rule, apply to a device, "the strictest rule and sub-rule resulting in the higher classification shall apply" (Annex VIII, 3.5). Accessories are classified in their own right (3.2). Software that drives a device or influences its use falls within the same class as the device; independent software is classified in its own right (3.3).

Class I

Rule 1 places non-invasive devices in class I unless another rule applies. Class I also covers some invasive and active devices. Apart from custom-made and investigational devices, the manufacturer issues the EU declaration of conformity after drawing up the technical documentation (Article 52(7)). A notified body is involved, for limited aspects only, in three cases, often written as Is, Im and Ir. These abbreviations are used in the guidance, not in the MDR itself:

MDCG 2021-24 rev.1 lists stethoscopes and wheelchairs pushed by hand as class I under Rule 1, and scalpels and scalpel handles as class I reusable surgical instruments under Rule 6.

Classes IIa and IIb (2a and 2b)

For class IIa and IIb devices, other than custom-made or investigational devices, a notified body assesses conformity and issues certificates (Articles 52(4), 52(6) and 56). The class comes from the rules, not from a general level of complexity or from how long a device stays in the body. MDCG 2021-24 rev.1 gives these examples:

Class III

Class III devices, other than custom-made or investigational devices, go through the conformity assessment under Article 52(3), and some devices through the additional consultation procedure in Article 54. Rule 8 places all implantable and long-term surgically invasive devices in class IIb unless an exception applies. The exceptions in class III include active implantable devices and their accessories, breast implants and surgical meshes, and total or partial joint replacements. Implantable cardiac pacemakers and hip and knee replacements are examples in MDCG 2021-24 rev.1.

Custom-Made and Investigational Devices

These routes do not apply to every device. Custom-made devices follow the procedure in Annex XIII and need the statement set out there (Article 52(8)). Only class III custom-made implantable devices additionally need a conformity assessment involving a notified body. Investigational devices are subject to Articles 62 to 81 (Article 52(13)).

Software: Rule 11

Rule 11 is new under the MDR. Software intended to provide information used to take decisions with diagnosis or therapeutic purposes is class IIa, unless those decisions may cause death or an irreversible deterioration of health (class III) or a serious deterioration of health or a surgical intervention (class IIb). Software intended to monitor physiological processes is class IIa, or class IIb for vital parameters where variations could result in immediate danger to the patient. All other software is class I. MDCG 2019-11 rev.1 (June 2025) explains the rule.

What Changed Compared With the MDD

Annex IX of the former Directive 93/42/EEC had 18 rules, the MDR has 22. Rules 11 (software), 19 (nanomaterials), 20 (devices that administer medicinal products by inhalation), 21 (devices composed of substances introduced through a body orifice or applied to the skin) and 22 (active therapeutic devices with an integrated or incorporated diagnostic function) have no counterpart in the directive. Former Rule 18 on blood bags was merged into Rule 2.

In Vitro Diagnostics

In vitro diagnostic devices are classified under the IVDR, in classes A, B, C and D (Article 47), by seven rules in its Annex VIII. MDCG 2020-16 rev.5 (September 2026) is the guidance. Notified bodies are listed in our IVDR overview.

EUDAMED and Pending Changes

Four EUDAMED modules have been mandatory since 28 May 2026: actors, UDI and device registration, notified bodies and certificates, and market surveillance (for competent authorities and the Commission). Devices already on the market that continue to be placed on the market must be registered by 28 November 2026, custom-made devices excepted (Article 123(3)(e) MDR). The vigilance and clinical investigation modules have no mandatory date yet (European Commission, EUDAMED).

The Commission's December 2025 proposal to simplify the MDR and IVDR (procedure 2025/0404(COD)) had not been adopted on 9 November 2026.

Sources

• Regulation (EU) 2017/745 (MDR), consolidated version of 9 November 2026, Articles 51, 52 and Annex VIII
• MDCG 2021-24 rev.1, Guidance on classification of medical devices (April 2026)
• MDCG 2019-11 rev.1, Qualification and classification of software (June 2025)
• Regulation (EU) 2017/746 (IVDR), consolidated version of 10 January 2025

Terms unclear? See our EU MDR glossary.

General information, not legal advice. Legal status as of 9 November 2026.

Get Demo