Someone has to write a class on the first page of your technical documentation. It decides whether you need a notified body, which Article 52 route you are on, how your documentation is sampled, how often you write a PSUR and whether a clinical investigation is compulsory. Change it in month nine and the quotation and the project plan change too.
Annex VIII of Regulation (EU) 2017/745 is not long. The difficulty is that most people read the 22 classification rules and skip Chapter II, where the provisions that move devices between classes sit.
Read Chapter II before you read the rules
Chapter I defines the terms, Chapter II the implementing rules, Chapter III Rules 1 to 22. Six implementing rules do most of the work:
- 3.1 — classification is governed by the intended purpose, not by what the device can do.
- 3.2 — devices used in combination are classified separately; accessories are classified in their own right.
- 3.3 — software that drives a device or influences its use takes that device’s class; independent software is classified in its own right.
- 3.4 — a device not intended for one specific part of the body is classified on its most critical specified use.
- 3.5 — where several rules or sub-rules apply, the strictest applies. Run every rule; do not stop at the first that fits.
- 3.6 — continuous use covers the whole duration of use of the same device, ignoring removal for cleaning, and accumulated use where an identical device immediately replaces it.
Chapter I fixes the durations: transient is continuous use under 60 minutes, short term 60 minutes to 30 days, long term over 30 days.
Four worked examples
1. A single-use hypodermic needle
Surgically invasive, transient, so Rule 6: Class IIa. Three sub-rules change that. As a reusable surgical instrument it is Class I, with notified body involvement limited to the reuse aspects (Article 52(7)). Intended specifically for direct contact with the heart, central circulatory system or central nervous system, it is Class III. Intended to administer a medicinal product in a potentially hazardous manner, it is Class IIb. Same steel, four classes.
2. A nasogastric feeding tube
Invasive with respect to a body orifice but not surgically invasive, so Rule 5. Indicated for 14 days it is short term: Class IIa. For 45 days it is long term: Class IIb. The Rule 5 exception for the oral cavity as far as the pharynx does not rescue you, because the tube terminates in the stomach. And under rule 3.6, a tube indicated for 28 days with instructions to replace it immediately with an identical tube is not a 28-day device.
3. A wound dressing
Rule 4 splits one product category across three classes. Sterile gauze acting as a mechanical barrier and absorbing exudate is Class I. A hydrogel dressing claiming to manage the wound micro-environment is Class IIa. A dressing principally intended for wounds that have breached the dermis and can heal only by secondary intent — a grade 4 pressure ulcer, a full-thickness burn — is Class IIb.
Now add an antimicrobial that would be a medicinal product in its own right, acting ancillary to the dressing. Rule 14 applies, rule 3.5 makes the strictest outcome prevail, and the dressing is Class III. Classifying a dressing under Rule 4 and stopping there is the commonest correction we issue.
4. A monitor and the software inside it
Under Rule 10, a consulting-room ECG allowing direct monitoring of vital physiological processes is Class IIa. A monitor intended for monitoring vital physiological parameters where the variations could cause immediate danger to the patient — respiration rate with an apnoea alarm — is Class IIb. The hardware can be near identical; the claimed purpose is the difference. Rule 9 does the same for therapy: a TENS unit is Class IIa, a ventilator Class IIb.
Rule 11 spans the full range. Software that only records and displays, such as a cycle-tracking app, is Class I. Software providing information used to take diagnostic or therapeutic decisions is Class IIa; Class IIb where those decisions may cause serious deterioration in health or a surgical intervention; Class III where they may cause death or irreversible deterioration. But embedded software controlling a Class IIb infusion pump is Class IIb under rule 3.3, because it drives the device.
What the class actually changes
Class IIa and Class IIb are different regimes, not two points on one scale. Article 52(6) has your notified body assess the technical documentation of one representative device per category of devices for Class IIa, and MDCG 2019-13 reads category as the relevant MDA/MDN codes in Commission Implementing Regulation (EU) 2017/2185. The Article 52 route for Class IIb is different again: Article 52(4) requires one per generic device group, which MDCG 2019-13 reads as the fourth level of the EMDN nomenclature — a far finer slice, so the same portfolio yields many more sampled files. Under Article 86 the PSUR is updated at least every two years for Class IIa and at least annually for Class IIb and III. And Article 61(4) makes clinical investigations compulsory for implantable and Class III devices, subject to the Article 61(6) exemptions; a non-implantable Class IIb device is not caught.
Where this goes wrong
Writing the intended purpose to reach the class you want. The notified body reads the IFU, the labelling and your marketing claims together. If the IFU says 14 days and the brochure shows the device in intensive care, you are assessed against the brochure. Leaving the purpose vague does not help: rule 3.4 then classifies on the most critical specified use.
Classifying the system instead of the parts. A wound drainage set is not one class: the surgically invasive cannula is Rule 7, short term, Class IIa; the tubing and collection container are Rule 1, Class I. Rule 3.2 lets you apply the highest class to the whole set, often the cheaper route, but that must be a decision, not an assumption. The same rule means a Class III device does not make its cleaning brush Class III.
Stopping at the rule that matches the device’s physical nature. Rules 1 to 13 sort by invasiveness and activity; Rules 14 to 22 catch what a device contains or does. A nanomaterial, an inhaled medicine, a systemically absorbed substance — each has its own rule and, under 3.5, can override the obvious answer.
Carrying a Directive class across unexamined. Class under Directive 93/42/EEC is not evidence of class under the Regulation — Rule 11 for software, and Rule 8 for mesh and joint replacements, moved large populations upwards.
Frequently asked questions
Who decides our class — us or the notified body?
You do. Classification is the manufacturer’s determination and must be justified in the technical documentation. The notified body reviews it and can reject it. If you disagree, Article 51(2) refers the dispute to the competent authority of the Member State of your registered place of business, or of your authorised representative — a formal route, and not a quick one.
Can our class change if we only change the instructions for use?
Yes — the point most often missed. Implementing rule 3.1 ties classification to intended purpose: extending an indication from 20 days to 35 days moves a Rule 5 device from Class IIa to Class IIb and changes your conformity assessment route. Treat every intended-purpose change as a classification review.
Our device is Class IIb. Do we need a clinical investigation?
Not by virtue of Article 61(4), which applies to implantable and Class III devices. You still need a clinical evaluation under Article 61(1) and Annex XIV, and your evidence is assessed for sufficiency whatever the class. What differs is the obligation to generate it through an investigation.
Is a Class I device sold sterile still Class I?
Yes. It stays Class I, but Article 52(7) brings a notified body in for the aspects relating to establishing, securing and maintaining sterile conditions. The same applies to Class I devices with a measuring function and to reusable surgical instruments.
A defensible classification is short: the intended purpose as written in the IFU, every rule you considered, why each did or did not apply, and the strictest outcome. Notified bodies accept that in a page. What they reject is a class asserted without one. Medfins prepares classification rationales as part of our CE marking and EU MDR work — send your intended purpose and device description and we will tell you which rules apply.
