EU MDR Medical Device Classification
Under EU MDR 2017/745, every medical device belongs to one of four risk classes: Class I, IIa, IIb or III. Class I has three sub-types: Is (sterile), Im (measuring) and Ir (reusable surgical instruments). You find the class by applying the 22 rules in Annex VIII to the device’s intended purpose. The class decides whether a Notified Body must take part in CE marking.
What Are the Medical Device Classes Under EU MDR?
Article 51 of the MDR places devices into classes by risk. The higher the class, the more the Notified Body reviews before the device can carry the CE mark. People write the classes with Roman numerals (Class IIa) or numbers (Class 2a). Both mean the same thing.
| Class | Risk | Typical examples | Notified Body? |
|---|---|---|---|
| Class I | Low | Non-sterile dressings, wheelchairs, walking aids, non-sterile examination gloves | No. The manufacturer self-declares. |
| Class Is | Low | Sterile gauze, sterile examination gloves | Yes, for sterility only |
| Class Im | Low | Medicine cups and spoons with dose markings | Yes, for the measuring function only |
| Class Ir | Low | Reusable scissors, forceps, retractors | Yes, for reprocessing only |
| Class IIa | Medium | Hearing aids, short-term urinary catheters, dental fillings | Yes |
| Class IIb | Medium to high | Infusion pumps, ventilators, bone plates and screws | Yes |
| Class III | High | Heart valves, coronary stents, hip and knee joint replacements | Yes, with the strictest review |
The class always depends on what the manufacturer says the device is for. Two similar products can fall into different classes if their intended purposes differ. For a side-by-side view, see Class I vs IIa vs IIb vs III comparison below.
How Do You Classify a Medical Device Under the MDR?
Classification is the first step of the CE marking process. It decides your conformity assessment route, how much clinical evidence you need and how often you report after launch.
- Define the intended purposeWrite down what the device does, for which patients and users, and every claim on the label, IFU and marketing material.
- Describe how the device touches the bodyIs it non-invasive, invasive through a body orifice, surgically invasive or implantable? Is it active (does it need a power source)?
- Set the duration of useTransient (under 60 minutes), short-term (60 minutes to 30 days) or long-term (over 30 days) of continuous use.
- Apply every rule that fitsCheck all 22 rules in Annex VIII. If more than one applies, the rule giving the highest class wins (Annex VIII, section 3.5).
- Record the justificationWrite the rule, your reasoning and the resulting class into the technical documentation (Annex II). Your Notified Body will check it.
Good to know: accessories are classified in their own right. Software that drives or influences a device takes the same class as that device. Standalone software is classified on its own under Rule 11.
What Do Duration, Invasiveness and Active Device Mean?
Annex VIII Chapter I defines the terms the rules use. Getting them right avoids most classification mistakes.
Transient use
Continuous use for less than 60 minutes. Examples: hypodermic needles, short diagnostic probes, single-use examination gloves.
Short-term use
Continuous use for 60 minutes to 30 days. Examples: urinary catheters after surgery, ECG electrodes for monitoring, daily-wear contact lenses.
Long-term use
Continuous use for more than 30 days. Examples: pacemakers, joint replacements, intraocular lenses, drug-eluting stents.
Invasive device
Any device that fully or partly enters the body, either through a body orifice or through the surface of the body.
Surgically invasive device
An invasive device that enters through the surface of the body, including through the mucous membranes of body orifices, with the help of or during surgery.
Implantable device
A device intended to be totally introduced into the body, or to replace an epithelial surface or the surface of the eye, and to stay there after the procedure.
Active device
A device that depends on a source of energy other than the human body or gravity. Software is also an active device.
Central circulatory and nervous system
Annex VIII lists the major vessels and heart structures, and the brain, meninges and spinal cord. Direct contact with them usually means Class III.
What Are the 22 Classification Rules in MDR Annex VIII?
The rules are grouped into four families. Each row below gives the main outcome of the rule. The full legal text has more detail, so always read the rule itself in Regulation (EU) 2017/745 and the examples in MDCG 2021-24.
Rules 1 to 4: Non-invasive devices
| Rule | Covers | Class |
|---|---|---|
| 1 | All non-invasive devices not covered by another rule | I |
| 2 | Channelling or storing blood, body liquids, cells, tissues, liquids or gases for later infusion or administration | IIa (blood bags IIb; otherwise I) |
| 3 | Modifying the biological or chemical composition of blood, body liquids or other liquids for infusion | IIb (IIa if only filtration, centrifugation or gas or heat exchange; III for substances used in vitro on human cells, tissues, organs or embryos before implantation or administration) |
| 4 | Contact with injured skin or mucous membrane | I as a mechanical barrier, for compression or to absorb exudates; IIb for wounds that breach the dermis and heal only by secondary intent; IIa in other cases |
Rules 5 to 8: Invasive devices
| Rule | Covers | Class |
|---|---|---|
| 5 | Invasive through a body orifice (not surgically invasive) | Transient I; short-term IIa; long-term IIb. Lower class in the oral cavity, ear canal or nasal cavity. IIa if connected to an active device of Class IIa or higher |
| 6 | Surgically invasive, transient use | IIa. Reusable surgical instruments I (Ir). III for direct contact with the heart, central circulatory system or central nervous system. IIb for ionising radiation, a biological effect, being absorbed, or hazardous delivery of medicines |
| 7 | Surgically invasive, short-term use | IIa. III for the heart, central circulatory or central nervous system, or a biological effect or absorption. IIb for ionising radiation, chemical change in the body (except in teeth) or delivering medicines |
| 8 | Implantable and long-term surgically invasive | IIb. IIa if placed in the teeth. III for the heart, central circulatory or central nervous system, active implants, breast implants, surgical meshes, total or partial joint replacements and spinal disc replacements |
Rules 9 to 13: Active devices
| Rule | Covers | Class |
|---|---|---|
| 9 | Active therapeutic devices that give or exchange energy | IIa; IIb if potentially hazardous or for therapeutic ionising radiation; III if they control or influence active implantable devices |
| 10 | Active devices for diagnosis and monitoring | IIa; IIb for monitoring vital parameters where changes could cause immediate danger, and for diagnostic or interventional ionising radiation |
| 11 | Software | IIa for information used in diagnosis or therapy; IIb if it could cause serious deterioration or surgery; III if it could cause death or irreversible deterioration; IIb for monitoring vital parameters with immediate danger; I for all other software |
| 12 | Active devices that administer or remove medicines or body liquids | IIa; IIb if potentially hazardous |
| 13 | All other active devices | I |
Rules 14 to 22: Special rules
| Rule | Covers | Class |
|---|---|---|
| 14 | Devices with an ancillary medicinal substance, including human blood or plasma derivatives | III |
| 15 | Contraception or prevention of sexually transmitted diseases | IIb; III if implantable or long-term invasive |
| 16 | Disinfecting, cleaning or sterilising | IIb for contact lens care; IIa for disinfecting or sterilising devices; IIb for disinfectants and washer-disinfectors used as the end point for invasive devices |
| 17 | Recording diagnostic images made by X-ray | IIa |
| 18 | Non-viable human or animal tissues or cells, or their derivatives | III (except animal-tissue devices that touch intact skin only) |
| 19 | Nanomaterials | III for high or medium internal exposure; IIb for low; IIa for negligible |
| 20 | Invasive through a body orifice to give medicines by inhalation | IIa; IIb if the device has an essential impact on the medicine’s efficacy and safety, or treats life-threatening conditions |
| 21 | Substances introduced into the body and absorbed or dispersed | III if systemically absorbed to achieve their purpose, or in the stomach or lower gut with systemic absorption; IIa on skin or in the nose or mouth up to the pharynx; IIb otherwise |
| 22 | Active therapeutic devices with an integrated diagnostic function that largely decides patient management | III (for example closed-loop systems and automated external defibrillators) |
Watch for updates: the European Commission has proposed a targeted revision of the MDR. This page will be updated if Annex VIII changes. The current classification guidance is MDCG 2021-24 Rev.1 (April 2026).
Which Conformity Assessment Route Applies to Each Class?
Article 52 sets the route for each class. Every class needs technical documentation (Annexes II and III), a clinical evaluation (Article 61) and an EU declaration of conformity.
| Class | Route | What the Notified Body reviews | After launch |
|---|---|---|---|
| I | Self-declaration (Article 52(7)) | Nothing | PMS report (Article 85) |
| Is, Im, Ir | Annex IX Chapters I and III, or Annex XI Part A | Only sterility, measuring function or reuse aspects | PMS report |
| IIa | Annex IX Chapters I and III, or Annex XI with Annex II and III documentation | QMS, plus technical documentation for at least one representative device per category | PSUR at least every 2 years |
| IIb | Annex IX Chapters I and III, or Annex X with Annex XI | QMS, plus technical documentation per generic device group. Every implantable IIb file, except sutures, staples, dental fillings, braces, crowns, screws, wedges, plates, wires, pins, clips and connectors | PSUR every year |
| III | Annex IX in full, or Annex X with Annex XI | QMS, plus the technical documentation of every device | PSUR every year, SSCP (Article 32) |
Implantable Class III devices, and Class IIb active devices that give or remove medicines, also go through the clinical evaluation consultation procedure with an expert panel (Article 54). Implantable and Class III devices normally need a clinical investigation (Article 61(4)).
Class comparison
How Do Class I, IIa, IIb and III Devices Compare?
The table summarises the main differences under the MDR. Examples are typical; the class of a real device depends on its intended purpose.
| Topic | Class I | Class Is / Im / Ir | Class IIa | Class IIb | Class III |
|---|---|---|---|---|---|
| Risk | Low | Low | Medium | Medium to high | High |
| Typical examples | Wheelchairs, non-sterile dressings, stethoscopes | Sterile gauze (Is), medicine measuring cups (Im), reusable scalpels (Ir) | Hearing aids, short-term catheters, dental fillings | Ventilators, infusion pumps, bone plates and screws | Heart valves, coronary stents, hip and knee replacements |
| Notified Body | No | Yes, for sterile, measuring or reuse aspects only | Yes | Yes | Yes |
| Conformity route (Art 52) | Technical documentation and EU declaration of conformity | Annex IX Ch I and III, or Annex XI Part A | Annex IX Ch I and III, or Annex XI | Annex IX Ch I and III, or Annex X with Annex XI | Annex IX in full, or Annex X with Annex XI |
| Technical documentation reviewed by the Notified Body | No | Only the relevant aspects | At least one representative device per category | At least one representative device per generic device group; every implantable IIb device, except listed well-established devices | Every device |
| Clinical investigation | Rarely | Rarely | Only if other clinical data is not sufficient | Required if implantable (with exemptions); otherwise only if data is not sufficient | Required, with limited exemptions |
| SSCP (Art 32) | No | No | No | Implantable only | Yes |
| Post-market report | PMS report, updated when needed | PMS report, updated when needed | PSUR at least every 2 years | PSUR every year | PSUR every year, submitted to the Notified Body via EUDAMED |
| UDI on the label from | 26 May 2025 | 26 May 2025 | 26 May 2023 | 26 May 2023 (implantable: 26 May 2021) | 26 May 2021 |
Every class needs a clinical evaluation (Article 61), a PRRC, EUDAMED registration and, for manufacturers outside the EU, an EU authorised representative.
Class I vs IIa
What Is the Difference Between Class I and Class IIa?
The biggest difference is the Notified Body. A Class I device is self-declared: the manufacturer prepares the technical documentation and signs the EU declaration of conformity. A Class IIa device needs a Notified Body to certify the quality management system and sample the technical documentation.
What usually keeps a device in Class I
- Non-invasive use on intact skin (Rule 1)
- Transient use through a body orifice (Rule 5)
- Reusable surgical instruments (Rule 6, Class Ir)
- Active devices not covered by other rules (Rule 13)
What usually moves a device to Class IIa
- Channelling or storing liquids for infusion (Rule 2)
- Short-term invasive or transient surgically invasive use (Rules 5 and 6)
- Active devices that deliver energy or monitor vital processes (Rules 9 and 10)
- Software that informs diagnosis or therapy decisions (Rule 11)
Watch out: sterile, measuring and reusable surgical Class I devices (Is, Im, Ir) still need a Notified Body for those specific aspects.
Class IIa vs IIb
What Is the Difference Between Class IIa and Class IIb?
Both classes need a Notified Body. Class IIb covers devices where a failure could cause more serious harm, so the review is deeper and reporting is more frequent.
| Situation | Class IIa | Class IIb |
|---|---|---|
| Surgically invasive duration | Transient or short-term use (Rules 6 and 7) | Long-term use and most implants (Rule 8) |
| Body orifice, long-term | In the oral cavity, ear canal or nasal cavity, if not absorbed | Elsewhere in the body (Rule 5) |
| Delivering energy | Exchanging energy with the body | Doing so in a potentially hazardous way, or using ionising radiation (Rule 9) |
| Monitoring | Monitoring vital physiological processes | Monitoring vital parameters where changes could mean immediate danger (Rule 10) |
| Software decisions | Diagnosis or therapy decisions | Decisions that could cause serious deterioration or surgery (Rule 11) |
| Injured skin | Managing the wound micro-environment | Wounds that breach the dermis and heal only by secondary intent (Rule 4) |
| PSUR | At least every 2 years | Every year |
Read more on the Class IIb medical device page.
Class IIb vs III
What Is the Difference Between Class IIb and Class III?
Many implants are Class IIb. A device moves to Class III when a specific high-risk condition applies.
- Location: direct contact with the heart, central circulatory system or central nervous system (Rules 6, 7 and 8).
- Named devices: breast implants, surgical meshes, joint replacements and spinal disc replacements (Rule 8).
- Materials and substances: an ancillary medicinal substance (Rule 14), non-viable human or animal tissue (Rule 18), or nanomaterial with high or medium internal exposure (Rule 19).
- Behaviour in the body: implants that are absorbed, have a biological effect or release medicines (Rule 8).
- Software and active devices: software decisions that could cause death or irreversible harm (Rule 11), and devices that control active implants (Rule 9).
For Class III, the Notified Body reviews the technical documentation of every device, implantable Class III devices go through the clinical evaluation consultation procedure (Article 54), and a clinical investigation is normally required.
Clinical evaluation
How Does Clinical Evidence Differ by Class?
Every device needs a clinical evaluation report under Article 61 and Annex XIV. What changes with the class is how much evidence is needed and how closely the Notified Body checks it.
Class I
Literature, post-market data and risk analysis are often enough. The CER is part of the self-declared technical file. PMCF is usually part of routine PMS.
Class IIa
A full literature review is expected, and equivalence may be claimed if it is shown under Annex XIV. The Notified Body samples the CER.
Class IIb
A robust CER with a detailed equivalence justification and a structured PMCF plan. Implantable IIb devices normally need a clinical investigation.
Class III
Clinical investigation data is normally required. Equivalence to another manufacturer’s device needs a contract giving full access to its technical documentation.
Useful guidance includes MDCG 2020-5 (equivalence), MDCG 2020-6 (sufficient clinical evidence for legacy devices) and MDCG 2020-13 (clinical evaluation assessment report).
Which Products Without a Medical Purpose Does the MDR Cover?
The MDR also regulates some aesthetic and other products that have no medical purpose. Annex XVI lists six groups. They must meet the common specifications in Regulation (EU) 2022/2346, and Regulation (EU) 2022/2347 sets the class of certain active products in these groups.
| Annex XVI group | Examples | Main risks |
|---|---|---|
| 1. Contact lenses and other items placed in or on the eye | Coloured or “fun” lenses without correction | Corneal abrasion, infection, vision loss |
| 2. Products implanted to change anatomy or fix body parts | Cosmetic breast implants (not tattoos or piercings) | Capsular contracture, rupture |
| 3. Dermal fillers injected under the skin or mucous membrane | Lip and wrinkle fillers | Allergic reaction, infection, vascular occlusion |
| 4. Equipment to reduce, remove or destroy fat tissue | Liposuction, lipolysis and lipoplasty devices | Bleeding, burns, nerve damage |
| 5. High-intensity light and radiation equipment for the skin | Lasers and IPL for hair or tattoo removal | Burns, scarring, eye injury |
| 6. Brain stimulation equipment | Electrical or magnetic stimulation to change neuronal activity | Seizures, headache, unknown long-term effects |
How Do EU MDR Classes Compare With FDA and UK Classes?
Many manufacturers sell in Europe, the USA and the UK at the same time. The systems look similar but use different rules, so a class does not transfer one-to-one. Always classify separately for each market.
| EU MDR 2017/745 | US FDA | UK (Great Britain) | |
|---|---|---|---|
| Classes | I (Is, Im, Ir), IIa, IIb, III | I, II, III | I, IIa, IIb, III |
| How the class is set | 22 rules in Annex VIII | Device type and product code in 21 CFR Parts 862–892 | UK MDR 2002 rules, based on the older EU directives |
| Typical route for higher risk | Notified Body certificate | 510(k), De Novo or PMA | UK Approved Body (UKCA) |
Northern Ireland follows the EU MDR. Check the current MHRA position on CE-marked devices in Great Britain before you plan your UK route.
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FAQs
Medical Device Classification: Frequently Asked Questions
Who decides the class of a medical device?
The manufacturer decides the class by applying the Annex VIII rules to the intended purpose. For Class Is, Im, Ir, IIa, IIb and III devices, the Notified Body checks that classification during conformity assessment. If they disagree, the competent authority of the manufacturer’s Member State decides (Article 51(2)).
What happens if more than one classification rule applies?
The strictest rule wins. Annex VIII section 3.5 says that if several rules apply to the same device, the rule giving the higher class is used. Record every rule you considered and why in the technical documentation.
Is Class 2a the same as Class IIa?
Yes. The MDR writes the classes with Roman numerals: I, IIa, IIb and III. People also write Class 1, Class 2a, Class 2b and Class 3, and sometimes Class 11a. These names all describe the same EU MDR risk classes.
Does software have its own classification rule?
Yes. Rule 11 covers software. Software that provides information for diagnosis or therapy is at least Class IIa, and can be IIb or III depending on the possible harm. Software that drives or influences a device takes the class of that device. MDCG 2019-11 explains how to apply it.
Is a Class I device CE marked without a Notified Body?
Yes, for plain Class I devices. The manufacturer prepares the technical documentation and signs the EU declaration of conformity. Sterile (Is), measuring (Im) and reusable surgical (Ir) Class I devices need a Notified Body for those specific aspects.
What is the difference between Class IIa and Class IIb?
Both need a Notified Body, but Class IIb devices carry higher risk. The Notified Body samples more technical documentation for IIb, reviews every implantable IIb device file (with some exemptions), and IIb devices need an annual PSUR instead of one at least every two years.
Can a Notified Body disagree with my classification?
Yes. The Notified Body reviews your classification. If you cannot agree, the matter goes to the competent authority of the Member State where you have your registered place of business, or where your authorised representative is based if you are outside the EU.
Which MDCG guidance covers classification?
MDCG 2021-24 is the main guidance on classifying medical devices under the MDR. Revision 1 was published in April 2026. For software, use MDCG 2019-11. The guidance explains each rule with examples but is not legally binding.