Rule 2 of Annex VIII of Regulation (EU) 2017/745 classifies non-invasive devices intended for channeling or storing blood, body liquids, cells or tissues, liquids, or gases for eventual infusion, administration, or introduction into the body. The default class is IIa. Rule 2 escalates to Class IIb when the device may be connected to an active medical device in Class IIa or a higher class, when it is intended for storing or channeling blood or other body liquids or for storing organs, parts of organs, or body cells and tissues, or when it is intended for the modification of the biological or chemical composition of the substances handled. Rule 2 lives in Annex VIII and is governed by Article 51 of the MDR, with authoritative interpretation in MDCG 2021-24 (October 2021).

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

TL;DR

  • Rule 2 covers non-invasive devices that channel or store blood, body liquids, cells or tissues, liquids, or gases intended for eventual infusion, administration, or introduction into the body.
  • Default classification under Rule 2 is Class IIa.
  • Rule 2 escalates to Class IIb when the device may be connected to an active medical device in Class IIa or a higher class, when it stores or channels blood or other body liquids, when it stores organs or body cells and tissues, or when it modifies the composition of what it carries.
  • A gravity-fed IV administration set that cannot be connected to an active infusion pump still lands at Class IIa. Connect it to a Class IIa pump and it becomes Class IIb.
  • Rule 2 is not a storage rule. It is an "on the way into the body" rule. The storage or channeling has to be for eventual administration.
  • Rule 2 overlaps with Rule 3 when the device also modifies what flows through it. When two rules apply, the highest class wins under the Section 2 implementing rules of Annex VIII.

Why Rule 2 deserves its own post

Rule 1 is the fall-through for non-invasive devices. Rule 2 is the first rule that actually pulls a whole class of everyday medical devices out of Class I and into Class IIa or higher. IV administration sets, blood bags, urine collection bags, transfer sets, gas delivery tubing, enteral feeding sets. The product categories Rule 2 catches are in every hospital storeroom, and a founder building any of them needs to know exactly where the default sits and what bumps the device higher.

The trap with Rule 2 is the escalation language. Four different triggers push a Rule 2 device from Class IIa to Class IIb, and founders routinely miss at least one. This post walks each trigger on its own, in the order the regulation presents them, and maps each to the concrete device categories where it bites.

For the wider classification picture, see MDR Annex VIII classification rules complete guide. For the sibling rule that governs the non-invasive default, see MDR classification Rule 1 non-invasive devices.

What Rule 2 actually says. Decoded

Rule 2 is a single rule inside Annex VIII Section 3 of Regulation (EU) 2017/745. The operative language defines the scope in two parts. Part one: the device is non-invasive. Part two: the device is intended for channeling or storing blood, body liquids, cells or tissues, liquids, or gases, for the purpose of eventual infusion, administration, or introduction into the body.

When both parts are true, the device is in Rule 2. The default class is IIa. From there, four distinct escalation conditions raise the class to IIb:

  1. The device may be connected to an active medical device in Class IIa or a higher class.
  2. The device is intended for use for channeling or storing blood or other body liquids, or for storing organs, parts of organs, or body cells and tissues.
  3. The device consists of tubing or storage containers intended for the purposes above and interacts with them in a way that modifies the biological or chemical composition of what it carries (in which case Rule 3 usually catches it first. See the overlap section below).
  4. The device is intended for the collection of body liquids where there is a backflow risk that could harm the patient under the intended conditions of use.

The exact wording of each escalation sub-case in Annex VIII Rule 2 should be checked against the current consolidated text of Regulation (EU) 2017/745 and cross-read against MDCG 2021-24 (October 2021) before a classification is written into the technical documentation. The rule is short, but every word carries weight.

The classification is always made against the intended purpose as defined in Article 2(12) of the MDR: "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." Rule 2 depends entirely on what the manufacturer claims the device is for, not on what a user might do with it.

Channeling versus storing. The two operative verbs

Rule 2 uses two verbs: channeling and storing. They are not the same, and the distinction matters when a device does one but not the other.

Channeling is movement. A tube carries a substance from somewhere to somewhere else. The substance is in transit. IV administration sets, transfer sets, enteral feeding tubes (the non-invasive segments), gas delivery tubing, and breathing circuit tubing are channeling devices.

Storing is containment. A container holds a substance until it is used, collected, or discarded. Blood bags, urine collection bags, IV fluid bags (when sold as primary containers), sample collection containers, and organ transport containers are storing devices.

A single device can do both. An IV set with an integrated drip chamber channels the fluid and momentarily stores a small volume in the chamber. The classification picks up both functions and applies the escalation triggers to each. The device is not split into two products.

The phrase "for the purpose of eventual infusion, administration, or introduction into the body" is the qualifier that narrows Rule 2. Storing a waste body liquid for disposal is still Rule 2 if the container is on the path from the patient, but a laboratory sample transport container used only in the lab, never intended to be re-introduced into the body, sits in Rule 1 as a non-invasive general-purpose container. Read the intended purpose carefully; the "for eventual administration into the body" qualifier is where borderline Rule 1 versus Rule 2 questions are decided.

Device examples that land in Rule 2

The working list of product categories that typically land under Rule 2 includes:

  • IV administration sets, including gravity sets, primary sets, secondary sets, and extension sets.
  • Blood collection bags, blood component bags, transfer bags, and apheresis bag systems.
  • Urine collection bags, drainage bags, and ostomy pouches used as collection containers.
  • Enteral feeding giving sets and enteral syringes used for nutrient administration.
  • Gas delivery tubing, oxygen therapy tubing, anaesthesia breathing circuits (non-invasive portions).
  • Containers for the storage and transport of organs, tissue grafts, or cell preparations.
  • Suction tubing and suction canisters on the path from the patient to the waste container.
  • Fluid warming disposables on the path from bag to patient.

Each of these sits at Class IIa by default under Rule 2 and moves up to Class IIb when one of the escalation triggers applies. A gravity IV set with no pump connection, no blood use, no composition change, and no organ storage: Class IIa. A blood bag: Class IIb (storing blood triggers the escalation). An IV set designed to connect to an active infusion pump: Class IIb. An organ transport container: Class IIb.

The four Rule 2 escalation conditions in detail

Escalation 1. Connection to an active device in Class IIa or higher

The first escalation catches devices that interface with active medical devices. The operative phrase is "may be connected". The test is not whether the device is always used with an active device, but whether the intended purpose includes connection to one. An IV set with a luer connector and an intended purpose that describes compatibility with active infusion pumps is caught, even if the same set can also be used gravity-fed.

The class of the active device matters. If the active device is Class I, Rule 2 stays at IIa. If the active device is Class IIa or higher. Which covers all active infusion pumps, syringe pumps, enteral feeding pumps, and most active fluid management systems. The Rule 2 device becomes IIb.

Escalation 2. Channeling or storing blood or other body liquids, or storing organs or body cells and tissues

The second escalation catches the high-consequence substances. Blood and other body liquids trigger it for both channeling and storing. Organs, parts of organs, and body cells and tissues trigger it for storing. A urine drainage bag channels a body liquid and is caught. A transport container for a kidney graft stores an organ and is caught. A blood bag is caught twice over. The result in each case is Class IIb.

The phrase "other body liquids" reaches further than blood. Bile, cerebrospinal fluid, lymph, synovial fluid, peritoneal dialysate once it has been in contact with the patient. All are body liquids. A device that channels or stores them for eventual reintroduction into the body, or for collection from the body, sits in the Class IIb range under this escalation.

Escalation 3. Modification of biological or chemical composition

The third escalation overlaps with Rule 3. If the device modifies what flows through it, Rule 3 typically catches it as the stricter rule. The Rule 2 text nonetheless carries an escalation for composition modification to ensure no gap exists. The practical answer is usually to classify the device under Rule 3 (which defaults to Class IIb, dropping to IIa for filtration, centrifugation, or exchange of gas or heat) and note in the technical documentation that Rule 2 also applies and is superseded under the Section 2 implementing rule that the highest class wins.

Escalation 4. Backflow risk for collection devices

The fourth escalation concerns devices that collect body liquids where a backflow event could harm the patient. This addresses devices like closed suction systems and certain drainage devices where a reverse-flow event could carry waste liquid back toward the patient. When the intended use includes this hazard profile and the device design accepts it, the Rule 2 device is pushed to IIb.

Common misclassifications under Rule 2

Assuming gravity IV sets are Class I. They are not. A gravity-fed IV administration set intended to deliver fluid into the body is still channeling a liquid for eventual administration into the body, and Rule 2 catches it at Class IIa. The absence of a pump does not demote the set to Rule 1.

Classifying a pump-compatible IV set as Class IIa because most users run it gravity-fed. The test is intended purpose, not dominant practice. If the labeling and IFU describe pump compatibility as an intended use, the connection-to-active-device escalation applies and the set is Class IIb.

Treating a blood bag as a simple container. Blood triggers the second escalation by itself. A blood bag is Class IIb under Rule 2 regardless of whether it is connected to anything.

Using Rule 1 for a urine collection bag. A urine drainage bag is collecting a body liquid from the body. It sits in Rule 2, and under the second escalation, at Class IIb.

Missing an overlap with Rule 3. A device that channels a substance and also modifies its composition (for example a heat-exchange tubing on a dialysis circuit) is caught by both Rule 2 and Rule 3. Rule 3 usually produces the higher class, which wins under the Section 2 implementing rules of Annex VIII.

Documenting the class without citing the specific Rule 2 sub-case. "Class IIa under Rule 2" is not enough for the technical documentation. The citation should read "Class IIa under Annex VIII Rule 2, because the device is a non-invasive [description] intended for channeling [substance] for eventual [administration route], and no Rule 2 escalation applies because [reason]." An auditor will ask for the latter.

The Subtract to Ship angle on Rule 2

The Subtract to Ship framework for MDR compliance treats classification as the second of four passes, after the Purpose Pass and before the Evidence Pass. Inside the classification pass for a Rule 2 device, subtraction is about writing the intended purpose with enough precision that only the escalations that genuinely apply are triggered.

A loose intended purpose invites every escalation. "For use with fluid delivery equipment" hands you the active-device escalation whether you meant to claim pump compatibility or not. A tight intended purpose. "for gravity-fed administration of sterile infusion solutions, not intended for use with active infusion pumps". Keeps the device at the Class IIa default if that is the correct class. The discipline is to match the intended purpose to the device you actually built and the evidence you actually have, and to let the class fall out of that. Subtracting claims you do not need is not gaming the rules. It is applying them to the real device.

Reality Check. Is your Rule 2 classification defensible?

  1. Is your device non-invasive in the Annex VIII Section 1 sense, or does any part of it breach the skin or a mucous membrane?
  2. Does the intended purpose describe channeling or storing a substance for eventual administration, introduction, or infusion into the body?
  3. Have you checked the four Rule 2 escalation conditions one by one against your intended purpose, not against your best-case usage scenario?
  4. If the device can be connected to an active pump, does the intended purpose claim that compatibility, and is the pump Class IIa or higher?
  5. Does the device channel or store blood, other body liquids, organs, parts of organs, or body cells and tissues?
  6. Does the device modify the composition of what it carries, and have you cross-checked Rule 3?
  7. Have you written the classification into the technical documentation with the specific Rule 2 sub-case, the intended purpose paragraph, and the reasoning?
  8. Have you cross-checked the classification against MDCG 2021-24 (October 2021)?

Frequently Asked Questions

What class is an IV administration set under MDR Rule 2? A non-invasive IV administration set intended for gravity-fed delivery of sterile solutions is Class IIa under Annex VIII Rule 2 of Regulation (EU) 2017/745. An IV set whose intended purpose includes connection to an active infusion pump in Class IIa or a higher class is Class IIb under the Rule 2 escalation for connection to active devices. The class depends on the intended purpose, not on whether the user happens to run the set with or without a pump.

Does Rule 2 cover blood bags? Yes. Blood bags are non-invasive devices that store blood for eventual administration into the body. They sit in Rule 2 and are pushed to Class IIb by the escalation that covers storing blood, other body liquids, organs, or body cells and tissues. A blood bag is Class IIb under Annex VIII Rule 2 regardless of whether it is sold as a single bag or as part of a multi-bag apheresis system.

What is the difference between Rule 1 and Rule 2 for a collection container? Rule 1 is the fall-through for non-invasive devices. Rule 2 specifically covers non-invasive devices that channel or store substances for eventual infusion, administration, or introduction into the body. A sample container used only for laboratory analysis and never intended for reintroduction into the body is typically Rule 1. A urine drainage bag collecting body liquid from the patient as part of the clinical care path is Rule 2, and under the body-liquids escalation, Class IIb.

How does Rule 2 interact with Rule 3? Rule 2 covers channeling and storing. Rule 3 covers non-invasive devices that modify the biological or chemical composition of what they carry. When a device both channels and modifies. For example, a heat-exchange segment on a bypass or dialysis circuit. Both rules apply. Under the Section 2 implementing rules of Annex VIII, when multiple rules apply the highest class wins. Rule 3 usually produces the higher class, so the device is classified under Rule 3.

Does Rule 2 apply to gas delivery tubing? Yes. Rule 2 explicitly includes gases among the substances covered. Non-invasive tubing that channels medical gases. Oxygen therapy tubing, nitrous oxide delivery tubing, breathing circuit tubing in its non-invasive segments. Sits in Rule 2 at Class IIa by default. If the tubing is intended to connect to an active Class IIa or higher device, the connection escalation pushes it to Class IIb.

Where is the authoritative interpretation of Rule 2? The authoritative interpretation is MDCG 2021-24. Guidance on classification of medical devices (October 2021), read together with the full text of Annex VIII of Regulation (EU) 2017/745. For borderline product categories, the Borderline and Classification Manual v4 (September 2025) records case-by-case decisions from the Borderline and Classification Working Group of the MDCG and is strong precedent when a similar device appears there.

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), Annex VIII Sections 1 (definitions), 2 (implementing rules), and 3 (Rule 2). Official Journal L 117, 5.5.2017.
  2. MDCG 2021-24. Guidance on classification of medical devices, October 2021.

This post is part of the Device Classification and Conformity Assessment series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. Rule 2 looks straightforward on the page and gets misapplied almost every time a founder classifies an IV set, a collection bag, or a transfer set without tracing each escalation trigger against the real intended purpose. When the exact wording of the intended purpose is load-bearing for the class, a short working session with a sparring partner who has run the exercise across fifty-plus certifications is usually the fastest way to a defensible answer.