---
title: MDR Annex VIII Classification Rules: The Complete Guide for Startups
description: MDR Annex VIII contains 22 classification rules. Here is the complete guide to how they work, grouped by device family, with the traps startups miss.
authors: Tibor Zechmeister, Felix Lenhard
category: Device Classification & Conformity
primary_keyword: MDR Annex VIII classification rules
canonical_url: https://zechmeister-solutions.com/en/blog/mdr-annex-viii-classification-rules-complete-guide
source: zechmeister-solutions.com
license: All rights reserved. Content may be cited with attribution and a link to the canonical URL.
---

# MDR Annex VIII Classification Rules: The Complete Guide for Startups

*By Tibor Zechmeister (EU MDR Expert, Notified Body Lead Auditor) and Felix Lenhard.*

> **Annex VIII of Regulation (EU) 2017/745 contains twenty-two classification rules that together determine the class of every medical device sold in the European Union. The rules are grouped into four families: Rules 1-4 cover non-invasive devices, Rules 5-8 cover invasive devices, Rules 9-13 cover active devices (including software under Rule 11), and Rules 14-22 cover special cases such as devices incorporating medicinal substances, nanomaterials, and contraceptive devices. A device can be hit by more than one rule at a time, and when that happens the highest applicable class wins. Classification is governed by Article 51 of the MDR, and the authoritative interpretation guide is MDCG 2021-24 (October 2021).**

**By Tibor Zechmeister and Felix Lenhard. Last updated 10 April 2026.**

---

## TL;DR

- MDR Annex VIII contains 22 classification rules that assign every medical device to Class I, IIa, IIb, or III based on intended purpose, invasiveness, duration of contact with the body, whether the device is active, and whether a special rule applies.
- Rules 1-4 cover non-invasive devices. Rules 5-8 cover invasive devices (including surgically invasive and implantable). Rules 9-13 cover active devices, with Rule 11 specifically for software. Rules 14-22 cover special categories such as medicinal substances, nanomaterials, contraception, disinfection, and devices composed of substances absorbed into the body.
- Rule 11 is the rule that reclassified most software as a medical device (MDSW) from Class I under the predecessor directive to Class IIa or higher under the MDR. MDCG 2019-11 Rev.1 (June 2025) is the guidance document for applying it.
- When more than one rule applies, the highest class wins. This is an implementing rule in Annex VIII, not a suggestion.
- The Borderline Manual v4 (September 2025) records case-by-case classification decisions from the Borderline and Classification Working Group of the MDCG and is strong precedent when a similar device appears there.
- Classification is the manufacturer's responsibility. A Notified Body can dispute it during conformity assessment, and a dispute late in the project is expensive. Get it right the first time, in writing, with a specific rule citation.

---

## Why this rule-by-rule guide exists

The previous post in this series, [MDR Device Classification Explained](/blog/mdr-device-classification-explained), is the hub for the classification cluster. It walks through the four device classes, the structure of Annex VIII, and the decision sequence. This post goes deeper. It takes each of the twenty-two rules in turn, in the order they appear in the Regulation, and explains what the rule covers, which devices it catches, the class it produces by default, the escalation paths, and the traps startups fall into.

A startup founder reading this post should be able to identify which rule applies to their device, what the class produced by that rule is, and which other rules might also apply and bump the class higher. Anyone who reads this post without also reading the actual Annex VIII text is doing it wrong. The paraphrases below exist to orient you; the classification itself must be made against the real Regulation text, cross-checked with MDCG 2021-24, and documented with the specific rule number and paragraph.

## How Annex VIII is structured — the short version

Annex VIII has three parts. Section 1 contains definitions (duration, invasiveness, active device, central nervous system, central circulatory system, and so on). Section 2 contains implementing rules — the meta-rules that govern how the classification rules are applied. Section 3 contains the twenty-two classification rules themselves.

The implementing rules in Section 2 are where most classification mistakes start. Three of them matter most:

- **Application of the rules is governed by the intended purpose of the devices.** The device you have on the bench is not what gets classified. The device described in the label, the instructions for use, the promotional materials, and the clinical evaluation is what gets classified. This reflects Article 2(12) of the Regulation, which defines intended purpose as "the use for which a device is intended according to the data supplied by the manufacturer on the label, in the instructions for use or in promotional or sales materials or statements and as specified by the manufacturer in the clinical evaluation" (Regulation (EU) 2017/745, Article 2, point 12).
- **If several rules, or if, within the same rule, several sub-rules, apply to the same device based on the device's intended purpose, the strictest rule and sub-rule resulting in the higher classification shall apply.** The highest class wins. Full stop.
- **Software, which drives a device or influences the use of a device, shall fall within the same class as the device.** Standalone software is classified on its own under Rule 11. Software that drives hardware inherits the hardware's class.

Skip the implementing rules and it does not matter how carefully you read Rules 1-22 — the classification will be wrong.

## Rules 1-4 — Non-invasive devices

The non-invasive family starts with the broadest default rule and then narrows down to specific categories.

### Rule 1 — The default for non-invasive devices

Rule 1 says all non-invasive devices are Class I unless one of the other rules applies. It is the fall-through rule for the non-invasive family. A non-sterile bandage, a wheelchair, a manual examination couch, a non-measuring stethoscope — these typically live in Rule 1 and end up as Class I.

The trap in Rule 1 is assuming it applies before checking whether Rules 2, 3, or 4 catch the device first. Rule 1 is the last rule you should land on, not the first.

### Rule 2 — Non-invasive devices for channelling or storing

Rule 2 covers non-invasive devices intended for channelling or storing blood, body liquids, cells or tissues, liquids, or gases for the purpose of eventual infusion, administration, or introduction into the body. The default is Class IIa. It escalates to Class IIb in certain sub-cases — for example, devices that can be connected to an active medical device in Class IIa or higher, or devices intended for storing or channelling blood or other body liquids or for storing organs, parts of organs, or body cells and tissues.

IV sets, urine collection bags, blood bags, and gas delivery tubing typically sit in Rule 2.

### Rule 3 — Non-invasive devices that modify biological or chemical composition

Rule 3 covers non-invasive devices intended for modifying the biological or chemical composition of human tissues, cells, or body liquids, or of other liquids intended for infusion into the body. The default is Class IIb, dropping to Class IIa when the treatment consists of filtration, centrifugation, or exchange of gas or heat.

Cell separation devices, haemodialysis equipment components, and blood component processing devices often sit in Rule 3.

### Rule 4 — Non-invasive devices in contact with injured skin or mucous membrane

Rule 4 covers non-invasive devices that come into contact with injured skin or mucous membrane. The class depends on the nature of the wound and the intended function: devices intended to be used as a mechanical barrier, for compression, or for absorption of exudates are Class I; devices used principally with wounds which have breached the dermis and can only heal by secondary intent are Class IIb; all other devices in this rule are Class IIa, including devices principally intended to manage the microenvironment of a wound.

Wound dressings are the classic Rule 4 devices. The Rule 4 traps are around mechanism of action: a dressing that just absorbs exudate is Class I, the same-looking dressing with an active ingredient or antimicrobial claim is a different class entirely.

## Rule 5 — Invasive devices with respect to body orifices

Rule 5 covers devices that are invasive with respect to body orifices (mouth, nose, ear canal, rectum, vagina, urethra) but are not surgically invasive. The class depends on duration:

- Transient use (less than 60 minutes continuous): Class I.
- Short-term use (60 minutes to 30 days): Class IIa, with exceptions — devices for transient use in the oral cavity as far as the pharynx, in the ear canal up to the ear drum, or in a nasal cavity, that are not liable to be absorbed by the mucous membrane, stay at Class I.
- Long-term use (over 30 days): Class IIb, with the same oral cavity/ear canal/nasal cavity exception dropping to Class IIa.

Rule 5 also escalates to Class IIa for devices intended to be connected to an active medical device in Class IIa or a higher class.

Examination gloves, suppositories, urinary catheters, nasal tampons, and dental impression trays all live somewhere in Rule 5 depending on duration and location.

## Rules 6-8 — Surgically invasive devices

Surgically invasive devices — devices that penetrate the body through the surface, either via the skin or an orifice, in the context of a surgical operation — are split by duration across Rules 6, 7, and 8.

### Rule 6 — Transient surgically invasive devices

Default is Class IIa. Escalations include:

- Class III if specifically intended to control, diagnose, monitor, or correct a defect of the heart or of the central circulatory system through direct contact with these parts of the body.
- Class III if specifically intended for use in direct contact with the central nervous system.
- Class IIb if intended specifically to supply energy in the form of ionising radiation.
- Class IIb if intended to have a biological effect or to be wholly or mainly absorbed.
- Class IIb if intended to administer medicinal products by means of a delivery system, if this is done in a manner that is potentially hazardous taking account of the mode of application.
- Class I for reusable surgical instruments — this is the Class Ir sub-category, requiring Notified Body involvement only for the reprocessing aspects.

Surgical scalpels, biopsy needles, short-duration catheters, and diagnostic probes used for less than 60 minutes typically sit in Rule 6.

### Rule 7 — Short-term surgically invasive devices

Default is Class IIa. Escalations are similar to Rule 6 and include Class III for direct contact with heart, central circulatory system, or central nervous system; Class IIb for ionising radiation, biological effect or absorption, chemical change or medicinal product administration in a potentially hazardous way; and Class IIb for substances introduced into the body that are absorbed or locally dispersed.

Short-term drainage catheters, post-operative drains, and devices used during procedures lasting from one hour to thirty days belong in Rule 7.

### Rule 8 — Long-term surgically invasive and implantable devices

Rule 8 is where most implants live. Default is Class IIb. Escalations to Class III cover:

- Devices intended to be placed in the heart or the central circulatory system, or in direct contact with these parts of the body.
- Devices intended to come into direct contact with the central nervous system.
- Devices intended to have a biological effect or to be wholly or mainly absorbed.
- Devices intended to undergo chemical change in the body (except devices placed in the teeth).
- Devices intended to administer medicinal products.
- Active implantable devices and their accessories (these are Class III).
- Breast implants and surgical meshes (Class III).
- Total or partial joint replacements (Class III, with certain ancillary components excluded).
- Spinal disc replacement implants and devices that come into contact with the spinal column (Class III, with certain exceptions).

Hip implants, pacemaker leads, heart valves, vascular stents, intraocular lenses, dental implants, and long-term drug-delivery implants all come out of Rule 8, each landing at either Class IIb or Class III depending on exactly which escalation applies.

## Rules 9-13 — Active devices

An active device is any device whose operation depends on a source of energy other than that generated by the human body for that purpose, or by gravity, and which acts by changing the density of or converting that energy. The active device family spans Rules 9 through 13.

### Rule 9 — Active therapeutic devices intended to administer or exchange energy

Default is Class IIa. Escalates to Class IIb if the characteristics are such that it can administer or exchange energy to or from the human body in a potentially hazardous way, taking account of the nature, density, and site of application of the energy. Active devices intended to control, monitor, or directly influence the performance of active therapeutic devices in Class IIb are also Class IIb.

Electrosurgical units, therapeutic lasers, ultrasound therapy devices, and infusion pumps for medicinal products (where Rule 12 does not already catch them) typically sit in Rule 9.

### Rule 10 — Active devices intended for diagnosis and monitoring

Default is Class IIa. Escalations:

- Class IIb if intended to supply energy which will be absorbed by the human body (with exceptions for simple illumination).
- Class IIb if intended to image in vivo distribution of radiopharmaceuticals.
- Class IIb if intended to allow direct diagnosis or monitoring of vital physiological processes, unless they are specifically intended for monitoring vital physiological parameters and the nature of variations of those parameters is such that it could result in immediate danger to the patient — in which case Class IIb still applies, but for ventilators and devices intended for monitoring vital physiological parameters in intensive care, Class IIb applies with additional considerations.
- Active devices intended to emit ionising radiation and intended for diagnostic or therapeutic interventional radiology, including devices which control or monitor such devices, or which directly influence their performance, are Class IIb.

Diagnostic imaging equipment, patient monitors, ECG machines, and pulse oximeters typically sit in Rule 10.

### Rule 11 — Software (see dedicated section below)

### Rule 12 — Active devices intended to administer or remove medicinal products, body liquids, or other substances

Default is Class IIa. Escalates to Class IIb if this is done in a manner that is potentially hazardous taking account of the nature of the substances involved, the part of the body concerned, and the mode of application.

Infusion pumps, dialysis machines, and suction devices typically sit in Rule 12.

### Rule 13 — All other active devices

Rule 13 is the active device fall-through. Any active device not caught by Rules 9, 10, 11, or 12 is Class I. Examination lamps, non-diagnostic active positioning aids, and similar simple active devices end up in Rule 13.

## Rule 11 — the software rule that reshaped SaMD

Rule 11 gets its own section because it is the single rule most likely to trip up startups. Before the MDR, a lot of software sat in Class I. Under Rule 11, most software with a diagnostic or therapeutic decision-support role is Class IIa or higher.

Rule 11 in substance works like this:

- Software intended to provide information which is used to take decisions with diagnosis or therapeutic purposes is Class IIa.
- It escalates to Class IIb if those decisions may cause serious deterioration of a person's state of health or a surgical intervention.
- It escalates to Class III if those decisions may cause death or an irreversible deterioration of a person's state of health.
- Software intended to monitor physiological processes is Class IIa.
- It escalates to Class IIb if it is intended to monitor vital physiological parameters, where the nature of variations of those parameters is such that it could result in immediate danger to the patient.
- All other software is Class I.

"All other software is Class I" sounds generous. It is not. The decision-support and physiological-monitoring categories between them catch the overwhelming majority of clinical software. MDCG 2019-11 Rev.1 (June 2025) is the authoritative guidance on qualification and classification of software under the MDR and IVDR. It contains decision trees and worked examples, and it is required reading for any SaMD founder.

The Rule 11 trap most founders hit is inheriting a pre-MDR assumption that their software is Class I. Re-read the rule against the real product. In most cases, the software is giving information that clinicians use to decide something, and that pushes it to IIa at minimum.

There is also a structural subtlety. Software that drives or influences a hardware device falls in the same class as the hardware device under the Section 2 implementing rules, not under Rule 11. Standalone software is classified on its own under Rule 11. A device that is hardware plus software has to be analysed as a whole.

We worked on exactly this situation. A combined hardware-software product where the software side was clearly Class IIa — no dispute — but the hardware side was disputed. The question was whether the hardware was plain Class I or Class I with measurement function. The distinction mattered because a measurement function triggers additional conformity assessment obligations under the Is/Im/Ir sub-classes. The team defended a Class I position for the hardware without measurement function by working carefully through the evidence: what the device actually measured, how the measurement results were used, whether the quantitative output met the Annex VIII definition of measurement function, and whether the intended purpose referred to measurement at all. The Notified Body accepted the Class I without measurement function position. This is not gaming the rules. It is applying them correctly with supporting evidence — the rules allow for judgment, and a rigorous argument backed by documentation produces outcomes.

## Rules 14-22 — Special rules

The special rules exist because some device categories do not fit cleanly into the non-invasive, invasive, or active families but still need specific risk treatment.

**Rule 14** — Devices incorporating a medicinal product as an integral part where the action of the medicinal product is ancillary to that of the device: Class III.

**Rule 15** — Devices used for contraception or prevention of the transmission of sexually transmitted diseases: Class IIb, unless they are implantable or long-term invasive, in which case Class III.

**Rule 16** — Devices specifically intended to be used for disinfecting, cleaning, rinsing, or, where appropriate, hydrating contact lenses: Class IIb. Devices specifically intended for disinfecting or sterilising medical devices: Class IIa, unless they are intended to be used for the disinfection of invasive devices, at the end of which they are Class IIb. Devices specifically intended for recording of diagnostic images generated by X-ray radiation are Class IIa.

**Rule 17** — Devices specifically intended for the recording of diagnostic X-ray images: Class IIa. (Rule 17 in the consolidated text addresses devices made using tissues or cells of human or animal origin, or their derivatives, which are non-viable or rendered non-viable: Class III, with specific exceptions.)

**Rule 18** — Devices incorporating or consisting of tissues or cells of human or animal origin, or their derivatives, which are non-viable or rendered non-viable: Class III, except where such devices are manufactured utilising tissues or cells of animal origin, or their derivatives, which are non-viable or rendered non-viable, and which are devices intended to come into contact with intact skin only, in which case Class I.

**Rule 19** — Devices incorporating or consisting of nanomaterial: Class III if they present a high or medium potential for internal exposure; Class IIb if they present a low potential for internal exposure; Class IIa if they present a negligible potential for internal exposure.

**Rule 20** — Invasive devices with respect to body orifices to administer medicinal products by inhalation: Class IIa, escalating to Class IIb if their mode of action has an essential impact on the efficacy and safety of the administered medicinal product or if they are intended to treat life-threatening conditions.

**Rule 21** — Devices that are composed of substances or of combinations of substances that are intended to be introduced into the human body via a body orifice or applied to the skin and that are absorbed by or locally dispersed in the human body: Class III if they, or their products of metabolism, are systemically absorbed by the human body in order to achieve the intended purpose; Class III if they achieve their intended purpose in the stomach or lower gastrointestinal tract and they, or their products of metabolism, are systemically absorbed by the human body; Class IIa if they are applied to the skin or if they are applied in the nasal or oral cavity as far as the pharynx and achieve their intended purpose on those cavities; Class IIb in all other cases.

**Rule 22** — Active therapeutic devices with an integrated or incorporated diagnostic function which significantly determines the patient management by the device, such as closed-loop systems or automated external defibrillators: Class III.

The special rules are the ones founders skip because they do not follow the invasive/active structure. Read them. At least one of them catches more startups than expected, especially Rule 19 (nanomaterial) for any device with an advanced material component, Rule 21 for anything absorbed into the body, and Rule 22 for closed-loop and autonomous therapeutic systems.

## Applying multiple rules at once

Annex VIII explicitly anticipates that more than one rule can apply to the same device. The implementing rule is clear: when multiple rules apply, the highest class wins. The same applies when multiple sub-rules within a single rule both catch the device — the stricter one governs.

The process looks like this. For each device, walk through every rule family and every rule within it. Do not stop at the first rule that fits. Write down every rule that could apply and the class it produces. Then take the highest class. That is the class of the device. The other rules still matter — they may require specific treatments in the technical documentation or the clinical evaluation — but the class is the highest one.

This is where MDCG 2021-24 and the Borderline Manual v4 earn their keep. If you are unsure whether a rule applies, MDCG 2021-24 will usually have the interpretation. If you are unsure whether a similar device has been classified before, the Borderline Manual v4 will usually have precedent.

## Common traps startups fall into with Annex VIII

**Reading Rules 1-22 without reading the implementing rules in Section 2.** The highest-class-wins principle, the accessory classification rule, and the software-driving-hardware rule all live in the implementing rules. Skipping them produces wrong classifications that look right.

**Stopping at the first rule that fits.** The second rule might produce a higher class. The highest class wins.

**Treating duration as product lifetime.** Transient, short-term, and long-term in Annex VIII refer to continuous intended use, not calendar time. A device used for twenty minutes per session, every week for two years, is transient.

**Assuming software is Class I because it was Class I under the predecessor directive.** Rule 11 is almost certainly the rule that applies. Re-classify under the MDR text, not the inherited assumption.

**Using a competitor's classification as a conclusion.** A competitor may be on a legacy certificate, may have a different intended purpose, or may simply be wrong. Competitor classifications are data points, not answers.

**Skipping the special rules in 14-22.** They catch nanomaterials, absorbed substances, closed-loop systems, tissue-derived materials, and contraceptives. At least one of these applies more often than founders expect.

**Documenting the class without citing the specific rule.** "Class IIa" is not a classification. "Class IIa under Annex VIII Rule X, based on intended purpose [paragraph], because [reason]" is a classification. A Notified Body auditor will ask for the latter.

## The Subtract to Ship angle on the rule-by-rule walk

The [Subtract to Ship framework for MDR compliance](/blog/subtract-to-ship-framework-mdr) treats classification as the second of four passes, after the Purpose Pass and before the Evidence Pass. Inside the classification pass, the rule-by-rule walk is where subtraction actually happens.

The discipline is: find every rule that could apply, identify the class each one produces, and then do the work that the highest applicable class requires — nothing more, nothing less. The failure mode is scoping the project for a higher class than the rules produce, or a lower one. Both drain runway. The first over-invests in documentation, QMS depth, and clinical evidence that are not actually required. The second under-invests and fails at the Notified Body gate.

Subtract to Ship does not mean finding the lowest class you can argue for. It means finding the lowest class you can defend, with a specific Annex VIII rule, a specific intended purpose, and an argument a Notified Body will accept. The hardware-without-measurement-function defence we mentioned earlier is a textbook example: it was not the softest class anyone could wish for, it was the correct class with rigorous supporting evidence.

## Reality Check — How well do you know the rules that apply to your device?

1. Can you name every rule in Annex VIII that could apply to your device, not just the one you landed on first?
2. For the rule you landed on, can you cite the specific paragraph and sub-rule?
3. Have you read the Section 2 implementing rules (highest-class-wins, accessory classification, software-driving-hardware)?
4. For software, have you read MDCG 2019-11 Rev.1 (June 2025) and applied Rule 11 rather than inheriting an MDD assumption?
5. Have you characterised the duration of use as continuous intended use, not product lifetime?
6. Have you cross-checked your classification against MDCG 2021-24 (October 2021)?
7. Have you searched the Borderline Manual v4 (September 2025) for comparable devices?
8. If a Notified Body auditor asked you tomorrow which rule applies and why, could you answer in one paragraph with a specific citation?
9. Have you written down the classification with the rule, the intended purpose, and the reasoning, so a future team member can reconstruct the logic?
10. Did you check the special rules (14-22) or did you stop at the non-invasive/invasive/active families?

## Frequently Asked Questions

**How many classification rules are in MDR Annex VIII?**
There are twenty-two classification rules, numbered 1 through 22. Rules 1-4 cover non-invasive devices, Rule 5 covers invasive devices with respect to body orifices, Rules 6-8 cover surgically invasive devices, Rules 9-13 cover active devices (with Rule 11 for software), and Rules 14-22 cover special categories such as devices incorporating medicinal substances, nanomaterials, and contraceptive devices. The rules are set out in Annex VIII of Regulation (EU) 2017/745, and the authoritative interpretation guide is MDCG 2021-24 (October 2021).

**What happens if more than one classification rule applies to my device?**
The highest class wins. This is an implementing rule in Section 2 of Annex VIII, not a suggestion. If Rule 9 says Class IIa and Rule 22 says Class III for the same device, the device is Class III. When sub-rules within a single rule also conflict, the stricter sub-rule governs. The job of the manufacturer is to identify every rule that could apply, determine the class each produces, and then take the highest.

**Which Annex VIII rule covers software?**
Rule 11 covers software intended as a medical device in its own right. Software that drives or influences a hardware device is classified together with the hardware under the implementing rules in Section 2 of Annex VIII, not under Rule 11. MDCG 2019-11 Rev.1 (June 2025) is the guidance document that walks through software qualification and classification under the MDR and IVDR with decision trees and examples. Read it before classifying any software product.

**Where does Rule 11 put decision-support software?**
Rule 11 puts software intended to provide information used to take decisions with diagnostic or therapeutic purposes in Class IIa by default. It escalates to Class IIb if those decisions may cause serious deterioration of health or require a surgical intervention, and to Class III if they may cause death or irreversible deterioration of health. Software that does not fall into this category or into the physiological-monitoring category is Class I, but that category is narrower than most SaMD founders assume.

**Is Rule 1 the default for every medical device?**
No. Rule 1 is the default only for non-invasive devices that are not caught by Rules 2, 3, 4, or any of the special rules. Invasive devices, active devices, and devices covered by the special rules do not fall back to Rule 1. Rule 13 is the active-device fall-through for active devices that are not caught by Rules 9-12. There is no single universal default rule — the fall-through depends on the family.

**How does the Borderline Manual v4 help with classification?**
The Borderline and Classification Manual v4 (September 2025) records case-by-case decisions made by the Borderline and Classification Working Group of the MDCG on specific product categories. When a device comparable to yours appears in the manual with a specific classification decision, that decision is strong precedent and can usually be cited to support your own classification. It also covers borderline questions — whether a product is a medical device at all, and whether it overlaps with medicinal products, biocides, cosmetics, or PPE. It is the first external reference to check after MDCG 2021-24.

**Can a Notified Body override my classification?**
Yes. Classification is the manufacturer's responsibility in the first instance, but the Notified Body reviews it during conformity assessment and can dispute it. If they disagree, they will require reclassification, and the project goes back to rebuild whatever downstream work was based on the wrong class. A dispute late in the project is expensive. The way to avoid it is to produce a defensible classification, in writing, with a specific rule citation and a reasoning paragraph that references the intended purpose under Article 2(12) of the Regulation.

## Related reading

- [The Subtract to Ship Framework for MDR Compliance](/blog/subtract-to-ship-framework-mdr) — the methodology that treats classification as the second of four passes.
- [MDR Device Classification Explained](/blog/mdr-device-classification-explained) — the pillar post on how classification works across all four classes.
- [Class I Medical Devices Under MDR](/blog/class-i-medical-devices-under-mdr) — what Class I means in practice, including the Is, Im, and Ir sub-categories.
- [Class IIa Medical Devices Under MDR](/blog/class-iia-medical-devices-under-mdr) — what Class IIa means, including conformity assessment routes.
- [Class IIb Medical Devices Under MDR](/blog/class-iib-medical-devices-under-mdr) — what Class IIb means, including implantable specifics.
- [Class III Medical Devices Under MDR](/blog/class-iii-medical-devices-under-mdr) — what Class III means, including mandatory clinical investigations.
- [MDR Classification Rule 11: Software](/blog/mdr-classification-rule-11-software) — the deep dive on Rule 11 for SaMD founders.
- [Intended Purpose vs. Intended Use Under MDR](/blog/intended-purpose-vs-intended-use-mdr) — the definition layer that drives every classification decision.
- [Seven Classification Mistakes Startups Make Under the MDR](/blog/7-classification-mistakes-startups-make-under-mdr) — the failure modes to avoid.

## Sources

1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, Article 2(12) (intended purpose), Article 51 (classification), Article 52 (conformity assessment procedures), Annex VIII Sections 1 (definitions), 2 (implementing rules), and 3 (Rules 1-22). Official Journal L 117, 5.5.2017.
2. MDCG 2021-24 — Guidance on classification of medical devices, October 2021.
3. MDCG 2019-11 Rev.1 — Guidance on Qualification and Classification of Software in Regulation (EU) 2017/745 — MDR and Regulation (EU) 2017/746 — IVDR, October 2019, Revision 1 June 2025.
4. Manual on borderline and classification for medical devices under Regulation (EU) 2017/745 and Regulation (EU) 2017/746, Version 4, September 2025 (Borderline and Classification Working Group of the MDCG).

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*This post is part of the Device Classification & Conformity Assessment series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. The rule-by-rule walk above is the orientation layer — the actual classification of a specific device must always be made against the full text of Annex VIII, cross-checked with MDCG 2021-24 and the Borderline Manual v4, and documented with a specific rule citation. When the complexity of a specific device exceeds what a blog post can resolve, a classification working session with a sparring partner who has run this exercise across fifty-plus certifications is usually the fastest way to a defensible answer.*

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*This post is part of the [Device Classification & Conformity](https://zechmeister-solutions.com/en/blog/category/classification) cluster in the [Subtract to Ship: MDR Blog](https://zechmeister-solutions.com/en/blog). For EU MDR certification consulting, see [zechmeister-solutions.com](https://zechmeister-solutions.com).*