How the EU classifies medical devices

Under Regulation (EU) 2017/745 a device falls into one of four classes: I, IIa, IIb or III. The class follows from the intended purpose of the device and its inherent risks, and it is determined by applying the classification rules in Annex VIII.¹ The regulatory identity of the product comes first. Whether the device is non-invasive, invasive with respect to a body orifice, surgically invasive, implantable, active or software decides which of the 22 rules in Annex VIII Chapter III attaches a class to it.

The four classes and where the rules sit

Article 51(1) divides devices into classes I, IIa, IIb and III and directs that classification be carried out in accordance with Annex VIII.¹ Annex VIII has three chapters. Chapter I gives definitions specific to classification, Chapter II gives implementing rules that govern how the individual rules are applied, and Chapter III contains the 22 classification rules themselves.¹

The rules are grouped by device type. Rules 1 to 4 cover non-invasive devices and rules 5 to 8 cover invasive devices. Rules 9 to 13 cover active devices. Rules 14 to 22 are special rules that cut across those groups.¹

Intended purpose governs the outcome

Section 3.1 of Annex VIII states that application of the classification rules is governed by the intended purpose of the device.¹ The same physical article with a different stated purpose can land in a different class. Section 3.4 adds that a device which is not intended to be used solely or principally in a specific part of the body is classified on the basis of its most critical specified use.¹

Section 3.5 resolves overlap. Where several rules apply, or several sub-rules within the same rule apply, the strictest rule and sub-rule resulting in the higher classification applies.¹ This means classification does not stop at the first rule that fits.

Combinations, accessories and software

Where a device is intended to be used in combination with another device, the classification rules apply separately to each device.¹ An accessory for a medical device is classified in its own right, separately from the device with which it is used.¹ Manufacturers coming from regimes where accessories inherit the parent device’s status will find this a material difference.

Software that drives a device or influences the use of a device falls within the same class as that device. Software independent of any other device is classified in its own right, which sends it to Rule 11.¹

Definitions that decide which rule applies

Chapter I fixes the terms the rules depend on. Duration of use has three bands: transient means normally intended for continuous use for less than 60 minutes, short term means between 60 minutes and 30 days, and long term means more than 30 days.¹ Section 3.6 explains how continuous use is calculated. It covers the entire duration of use of the same device without regard to temporary interruption during a procedure or temporary removal for cleaning or disinfection. It also covers the accumulated use of a device intended by the manufacturer to be replaced immediately with another of the same type.¹

Other defined terms carry equal weight:

• Body orifice includes any natural opening, the external surface of the eyeball and any permanent artificial opening such as a stoma.
• Surgically invasive device covers penetration through the body surface with the aid or in the context of a surgical operation, and any device producing penetration other than through a body orifice.
• Reusable surgical instrument means an instrument for the following procedures, without connection to an active device, intended to be reused after cleaning, disinfection or sterilisation.
  • cutting
  • drilling
  • sawing
  • scraping
  • clamping
  • retracting
  • clipping
  • similar procedures
• Active therapeutic device means an active device used to support, modify, replace or restore biological functions or structures for treatment or alleviation of illness, injury or disability.
• Central circulatory system is an enumerated list of named vessels, including the aorta from the aorta ascendens to the bifurcatio aortae, the coronary arteries and both venae cavae.
• Central nervous system means the brain, meninges and spinal cord.
• Injured skin or mucous membrane means an area presenting a pathological change or change following disease or a wound.¹

Section 3.7 adds that a device allows direct diagnosis when it provides the diagnosis by itself or provides decisive information for the diagnosis.¹

Non-invasive devices under rules 1 to 4

Rule 1 places all non-invasive devices in class I unless a later rule applies.¹ Rule 2 covers non-invasive devices for channelling or storing the following for eventual introduction into the body.

• blood
• body liquids
• cells
• tissues
• liquids
• gases

These are class IIa if they may be connected to a class IIa, IIb or III active device, or if they are used for channelling or storing blood or other body liquids or for storing organs, parts of organs or body cells and tissues. Blood bags are class IIb, and other such devices are class I.¹

Rule 3 places non-invasive devices intended to modify the biological or chemical composition of tissues, cells, blood or other liquids for implantation or administration in class IIb. Where the treatment consists of filtration, centrifugation or exchange of gas or heat, the class is IIa. A non-invasive device consisting of a substance or mixture of substances used in vitro in direct contact with human cells, tissues or organs taken from the body is class III.¹

Rule 4 addresses contact with injured skin or mucous membrane. Devices acting as a mechanical barrier, for compression or for absorption of exudates are class I. Devices principally for injuries which have breached the dermis and can only heal by secondary intent are class IIb. Devices principally intended to manage the micro-environment of the injury are class IIa, as are all other cases. The rule also applies to invasive devices that contact injured mucous membrane.¹

Invasive devices under rules 5 to 8

Rule 5 covers invasive devices with respect to body orifices other than surgically invasive devices, where there is no connection to an active device or a connection to a class I active device. Transient use gives class I, short-term use gives class IIa and long-term use gives class IIb. Reductions apply for use in the oral cavity as far as the pharynx, in an ear canal up to the ear drum or in the nasal cavity. Connection to a class IIa, IIb or III active device gives class IIa.¹

Rule 6 sets class IIa as the baseline for transient surgically invasive devices, with these exceptions:

• class III where intended specifically to control, diagnose, monitor or correct a defect of the heart or of the central circulatory system through direct contact.
• class I where the device is a reusable surgical instrument.
• class III where intended specifically for direct contact with the heart, central circulatory system or central nervous system.
• class IIb where intended to supply energy in the form of ionising radiation.
• class IIb where the device has a biological effect or is wholly or mainly absorbed.
• class IIb where intended to administer medicinal products by a delivery system in a potentially hazardous manner.¹

Rule 7 applies to short-term surgically invasive devices and again starts at class IIa. Cardiac, central circulatory and central nervous system contact give class III, as does a biological effect or wholesale absorption. Ionising radiation, chemical change in the body other than in the teeth, and administration of medicines give class IIb.¹

Rule 8 places all implantable devices and long-term surgically invasive devices in class IIb, with placement in the teeth reduced to class IIa. Class III results where the device contacts the heart, central circulatory system or central nervous system. It also results where the device has a biological effect or is wholly or mainly absorbed. The same applies where the device undergoes chemical change in the body outside the teeth or administers medicinal products. The following are class III.

• active implantable devices and their accessories
• breast implants
• surgical meshes
• total or partial joint replacements
• spinal disc replacement implants
• implantable devices contacting the spinal column

Ancillary components such as screws, wedges, plates and instruments are excepted from the joint replacement and spinal entries.¹

Active devices under rules 9 to 13

Rule 9 places active therapeutic devices that administer or exchange energy in class IIa, moving to class IIb where energy may be administered or exchanged in a potentially hazardous way. Devices controlling, monitoring or directly influencing class IIb active therapeutic devices are class IIb, as are devices emitting ionising radiation for therapeutic purposes. Devices controlling, monitoring or directly influencing active implantable devices are class III.¹

Rule 10 covers active devices for diagnosis and monitoring. Class IIa applies where the device supplies energy absorbed by the body, images in vivo distribution of radiopharmaceuticals, or allows direct diagnosis or monitoring of vital physiological processes. Class I applies to devices intended to illuminate the patient’s body in the visible spectrum. Class IIb applies where monitoring covers vital physiological parameters whose variation could place the patient in immediate danger, and to active devices emitting ionising radiation for diagnostic or therapeutic radiology.¹

Rule 11 governs standalone software. Software providing information used to take decisions with diagnosis or therapeutic purposes is class IIa. It is class III where those decisions may cause death or irreversible deterioration of health, and class IIb where they may cause serious deterioration of health or a surgical intervention. Software intended to monitor physiological processes is class IIa, rising to IIb for monitoring of vital physiological parameters where variation could result in immediate danger. All other software is class I.¹

Rule 12 places active devices that administer or remove medicinal products, body liquids or other substances in class IIa, or class IIb where this is done in a potentially hazardous manner. Rule 13 places all other active devices in class I.¹

Special rules 14 to 22

The special rules override the general pattern for defined product types. Rule 14 places devices incorporating an ancillary medicinal substance in class III. Rule 15 places contraceptive devices and devices preventing transmission of sexually transmitted diseases in class IIb, or class III where implantable or long-term invasive. Rule 16 covers contact lens care products at class IIb and devices for disinfecting or sterilising medical devices at class IIa, with class IIb for disinfecting solutions and washer-disinfectors used on invasive devices as the end point of processing. Rule 17 places devices specifically intended for recording diagnostic images generated by X-ray radiation in class IIa.¹

Rule 18 places devices manufactured utilising non-viable human or animal tissues, cells or derivatives in class III, with an exception for animal-derived devices contacting intact skin only. Rule 19 grades devices incorporating or consisting of nanomaterial by potential for internal exposure: class III for high or medium, class IIb for low and class IIa for negligible. Rule 20 covers inhalation administration of medicinal products through body orifices at class IIa, rising to IIb where the mode of action has an essential impact on efficacy and safety or the device treats life-threatening conditions. Rule 21 classifies substance-based devices introduced via a body orifice or applied to the skin, reaching class III where systemic absorption achieves the intended purpose. Rule 22 places active therapeutic devices with an integrated diagnostic function that significantly determines patient management, such as closed loop systems and automated external defibrillators, in class III.¹

Disputes and reclassification

A dispute between the manufacturer and the notified body arising from the application of Annex VIII is referred for decision to the competent authority of the Member State where the manufacturer has its registered place of business. Where the manufacturer has no such place of business in the Union and has not designated an authorised representative, the matter goes to the competent authority of the Member State of the authorised representative referred to in Annex IX Section 2.2. Where the notified body is established in another Member State, the competent authority decides after consulting the authority that designated the notified body. That decision is notified to the MDCG and the Commission and made available on request.¹

At the request of a Member State the Commission decides by implementing act on the application of Annex VIII to a given device, category or group of devices. It consults the MDCG before deciding. The Commission may also take such a decision on its own initiative after consulting the MDCG. It may do so at the request of a Member State or on its own initiative, after consulting the MDCG. It may also reclassify a device, category or group by derogation from Annex VIII for public health reasons based on new scientific evidence or on vigilance and market surveillance information. Further implementing acts may resolve issues of divergent interpretation. These acts are adopted under the examination procedure in Article 114(3).¹

What the class determines beyond conformity assessment

Class governs the transitional deadlines in Article 120. Devices holding a certificate issued under Directive 90/385/EEC or 93/42/EEC that remains valid by virtue of Article 120(2) may be placed on the market or put into service until 31 December 2027. That date applies to all class III devices and to class IIb implantable devices, excluding the following.

• sutures
• staples
• dental fillings
• dental braces
• tooth crowns
• screws
• wedges
• plates
• wires
• pins
• clips
• connectors

The date is 31 December 2028 for other class IIb devices, for class IIa devices and for class I devices placed on the market in sterile condition or having a measuring function.¹

These extensions depend on the conditions in Article 120(3c). The device must continue to comply with the applicable directive, there must be no significant changes in design and intended purpose, and the device must not present an unacceptable risk. A quality management system under Article 10(9) had to be in place by 26 May 2024. A formal application to a notified body had to be lodged by 26 May 2024 and a written agreement signed by 26 September 2024.¹

Article 120(3b) addresses up-classification. A device for which Directive 93/42/EEC required no notified body may be placed on the market until 31 December 2028. This applies where the declaration of conformity was drawn up before 26 May 2021 and notified body involvement is now required.¹

Class also sets the UDI carrier timetable in Article 123(3). Article 27(4) applied to implantable and class III devices from 26 May 2021, to class IIa and IIb devices from 26 May 2023 and to class I devices from 26 May 2025. For reusable devices required to bear the UDI carrier on the device itself, Article 27(4) applied to implantable and class III devices from 26 May 2023 and to class IIa and IIb devices from 26 May 2025. For class I reusable devices in that category it applies from 26 May 2027.¹

Questions people also ask

Who decides the class of a device in the EU?

The manufacturer applies Annex VIII to its own device in the first instance, since classification follows from the intended purpose the manufacturer assigns. Where the manufacturer and a notified body disagree, Article 51(2) sends the dispute to the competent authority of the Member State where the manufacturer has its registered place of business. The Commission may also settle the application of Annex VIII to a device, category or group of devices by implementing act under Article 51(3) to (6).¹

What class is standalone medical software under the EU rules?

Rule 11 assigns the class. Software providing information used to take diagnostic or therapeutic decisions is class IIa as a baseline. It rises to class IIb where the decision may cause serious deterioration of health or a surgical intervention, and to class III where it may cause death or irreversible deterioration. Software monitoring vital physiological parameters whose variation could place the patient in immediate danger is class IIb. Remaining software is class I.¹

How is duration of use counted when a device is removed and reinserted?

Section 3.6 of Annex VIII treats continuous use as the entire duration of use of the same device, disregarding temporary interruption during a procedure or temporary removal for cleaning or disinfection. Whether an interruption is temporary is judged against the duration of use before and after it. Where the manufacturer intends the device to be replaced immediately by another of the same type, the accumulated use counts.¹

How are accessories to a medical device classified?

Annex VIII Section 3.2 provides that an accessory is classified in its own right, separately from the device with which it is used. The same section requires the classification rules to be applied separately to each device where two devices are intended for use in combination.¹

What happens when two classification rules give different answers?

Section 3.5 of Annex VIII applies the strictest rule and sub-rule, producing the higher classification. This applies both across rules and between sub-rules within a single rule.¹

Until when may devices certified under the old directives remain on the market?

Article 120(3a) sets 31 December 2027 for class III devices and class IIb implantable devices outside the listed exceptions, and 31 December 2028 for other class IIb devices, class IIa devices and class I devices that are sterile or have a measuring function. The conditions in Article 120(3c) must be satisfied, including the quality management system and notified body application milestones of 2024. Devices lawfully placed on the market under those provisions may continue to be made available or put into service under Article 120(4).¹

Footnotes

1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and repealing Council Directives 90/385/EEC and 93/42/EEC. Consolidated version of 2026-07-19. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02017R0745-20260719 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³ ↩³⁴ ↩³⁵ ↩³⁶ ↩³⁷ ↩³⁸ ↩³⁹ ↩⁴⁰