Risk Classification of Medical Devices

What does the risk classification of medical devices mean and why is it so important?

Classification of medical devices is the process of assigning a device to a class based on its intended purpose and the resulting risk to patients and users.

Under Regulation (EU) 2017/745 (MDR), a device is assigned to Class I, IIa, IIb or III. This risk class largely determines the regulatory effort: from technical documentation and clinical evaluation to market access. The higher the risk, the stricter the requirements for evidence, assessment and surveillance.

EU MDR vs. FDA Classification

The classification of medical devices in the European Union (EU) and the United States (US) is different not only in terms of terminology, but also in terms of the overall regulatory approach. While the EU follows a rule-based classification system, the US relies on a product- and risk-based comparative assessment.

In the EU risk classification according to the MDR regulations (Annex VIII) is based on criteria such as invasiveness, duration of use and intended purpose. A structured decision path is provided for each product. The assessment and approval are mainly carried out by Notified Bodies.

In the US classification is based on risk and what is known as substantial equivalence, which refers to the similarity to already approved products (predicate devices). The FDA is directly responsible for testing and approval via procedures such as 510(k) or PMA (premarket approval).

Risk classes of the MDR

Medical devices are classified into four main classes in accordance with the rule-based approach of the MDR:

Class I, IIa, IIb, and Class III

Class I has three subcategories:
Is (sterile), Im (measuring), and Ir (reusable surgical instruments)

In-Vitro Diagnostics (IVD)

In vitro diagnostic medical devices are covered by IVDR (EU) 2017/746, which provides for its own classification system:

Classes A, B, C, and D

US Approval System (FDA)

In the United States, medical devices are classified into three risk classes by the Food and Drug Administration (FDA) based on a risk- and comparative-based approach:

Class I, Class II, and Class III

What are the risk classes for medical devices according to MDR?

The MDR regulates that products are assessed based on their intended use, duration of use, location of contact in the body, and invasiveness. The deeper a product is inserted into the body and the longer it remains in the body, the higher the risk. The higher the risk, the more intensive the requirements, especially with regard to the involvement of a Notified Body, Clinical Data, Conformity Assessment, and Post-Market Surveillance.

How does classification work?

Classification is a process consisting of the following steps:

Specify the intended use.
The purpose defined by the manufacturer is binding.

Does the product fall under the MDR at all?
Medical device, pharmaceutical, biocide, cosmetics, nutritional supplement.

Apply all applicable rules.
Duration of contact, invasiveness, active/non-active, affected body part; these factors determine the applicable rules from Annex VIII.

The strictest rule applies.
If multiple rules apply, the one that results in the highest class determines the classification for the product as a whole.

Intended Purpose as a Core Regulatory Criterion

The intended purpose has an often underestimated but central role in the entire MDR process.
Specifically, the intended purpose regulates:

the legal categorisation of the product (e.g. cosmetic, biocide, medicinal product, medical device)
the requirements for clinical performance, compatibility and scope of clinical evidence, and thus forms the basis for the “benefit-risk assessment”
the placement on the market of the product and its commissioning
the normal conditions of use
the scope of the general safety and performance requirements and the design, and manufacturing requirements
the instructions for use, the summary of safety and clinical performance, and the technical documentation (product description and specification)

Warum entscheidet die Zweckbestimmung über den regulatorischen Status?

Example: Not all adhesive tapes are the same

Product 1: Scotch Tape

Intended purpose:
to connect two objects

Product 2: Band-Aid

Intended purpose:
to cover minor open wounds and prevent infections

Product 3: Surgical adhesive strips

Intended purpose:
for treating minor cuts, instead of sutures, staples, or clips

What is the significance of the risk class and intended use in the approval process?

The intended purpose of a medical device determines its intended use and is therefore directly linked to its risk class. The risk class is highly significant and has a major impact on the manufacturer’s activities, as almost all processes are tailored to it.

The risk class affects the requirements for:

the Quality Management System and a Post-Market-Surveillance System
the Conformity Assessment Procedure, e.g., unannounced on-site audits and random sampling by notified bodies
the requirements for Technical Documentation, EU declaration of conformity, UDI database
the scope of product testing

How is the risk class of a medical device determined?

In the EU, classification is carried out in accordance with the classification rules in Annex VIII of the MDR. Annex VIII contains 22 rules that provide a structured decision-making process for each product. The rules can be divided into four groups: non-invasive devices, invasive devices, active devices, and special rules (including those for substances, nanomaterials, and software).

The specific conformity assessment procedure that applies is then determined by the identified class and the corresponding annexes.

Duration of Use

Place of Application

Reusable Surgical Instrument

Active Medical Device

Use of Biological Material

< 60

Minutes

< 30 Days

> 30 Days

Degree of
Invasivity

Central Circulatory System / Nervous System

therapeutic

diagnostic

Human

Animal

There is no blanket assignment of medical devices to a fixed risk class; the assignment applies to a specific, individual product.

If problems arise with the classification, the applicant, after reviewing all available literature on differentiation or classification, may first contact the relevant state authority or a Notified Body and, finally, submit an application for classification and/or differentiation pursuant to Section 6(2) of the Medical Devices Act (MPDG) to the Federal Institute for Drugs and Medical Devices (BfArM).

What is the difference between the classes?

The difference lies in the potential risk and, consequently, in the complexity of the authorization process.

Non-active devices function without their own energy source, relying solely on their physical properties.
Rules 1 through 4 apply to non-invasive versions.
Examples: bandages, non-powered catheters, surgical instruments.

Invasive devices penetrate the body either fully or partially. The classification is determined by how the product is introduced (through a body orifice or surgically), how long it remains in place, and where it acts; in particular, contact with the central circulatory system or central nervous system significantly increases the class. Rules 5 through 8 apply to invasive products.

Active devices rely on an energy source not generated by the human body or gravity and convert this energy.
Rules 9 through 13 apply to these devices.
Examples: infusion pumps, ventilators, surgical lasers.

The same medical function may fall into a different risk class depending on the product group.

The 22 classification rules (MDR Annex VIII)

The rules are set out in Annex VIII of the MDR. The Medical Device Coordination Group (MDCG) published the MDCG 2021-24 guidance, explaining each rule with practical examples and graphical decision trees. The current version is Rev.1 (April 2026).

Group	Rule	Scope	Typical class
Non-invasive	1	No contact or intact skin only (fallback rule)	I
	2	Channeling/storing blood, fluids, gases for later administration	IIa (I/IIb)
	3	Modifying the biological/chemical composition of blood, tissues, fluids	IIb (IIa/III)
	4	Contact with injured skin or mucous membrane	I/IIa/IIb
Invasive (body orifice)	5	Introduction into body orifices, non-surgical	I/IIa/IIb
Surgically invasive	6	Transient use (< 60 min)	IIa (I/IIb/III)
	7	Short-term use (60 min – 30 days)	IIa (IIb/III)
	8	Long-term use (> 30 days) and implantable devices	IIb (IIa/III)
Active	9	Therapeutic — deliver/exchange energy	IIa (IIb)
	10	Diagnosis/monitoring, diagnostic/therapeutic radiology	IIa (I/IIb)
	11	Software (MDSW) — decision, diagnosis, monitoring	I/IIa/IIb/III
	12	Administration/removal of medicines, fluids, substances	IIa (IIb)
	13	All other active devices (fallback rule)	I
Special rules	14	Integrated medicinal substance (ancillary action)	III
	15	Contraception / prevention of sexually transmitted diseases	IIb (III)
	16	Disinfection, cleaning, sterilization of devices	IIa (IIb)
	17	Recording of X-ray diagnostic images	IIa
	18	Tissues/cells of human/animal origin or derivatives	III (I)
	19	Nanomaterials	IIa/IIb/III
	20	Administration of medicines by inhalation	IIa (IIb)
	21	Substance-based — introduced via orifice / applied to skin	IIa/IIb/III
	22	Active therapeutic with integrated diagnostic function (closed-loop, AED)	III

Which classification rule applies?

A product rarely falls under just one rule. If multiple rules apply, the classification is not determined by the average or the most obvious rule, but by the rule that results in the highest class. This rule determines the classification for the product as a whole. This also applies within a single rule: if multiple sub-rules apply, the strictest one applies.

Class	Risk	Application	Market access
Class I	low	mostly non-invasive (e.g., bandages, wheelchairs)	Typically self-certification without a Notified Body
Class IIa	medium	often short-term use (e.g. hearing aids, much software)	Notified Body required
Class IIb	increased	long-term contact or active devices (e.g. infusion pumps)	Notified Body required
Class III	high	life-sustaining or implantable devices (e.g. heart valves)	Highest requirements incl. clinical data

How can WQS help with classification?

The Classification is essential for a fast, cost-effective, and safe approval.

WQS provides expert guidance throughout the entire conformity assessment process: We determine the regulatory status of your product, work with you to define its intended use in a way that supports its classification, and apply the rules from Annex VIII in a well-reasoned manner. We document the selected class in a way that stands up to scrutiny, ensuring that the rationale withstands an audit and is not created only in response to a request for additional information.

Analysis and definition of your intended purpose
Identification of the correct risk class according to MDR
Preparation of technical documentation and classification justification
Support in communication with notified bodies
Advice on software, accessories, and IVD classification

Do I need a Notified Body, or is self-certification acceptable?

Only Class I products (excluding special cases) may be self-certified.

As soon as a product falls under Class Is, Im, Ir, IIa, IIb, or III, a Notified Body must be involved. Colloquially, the Notified Body is often referred to as “TÜV”; in fact, TÜV organizations (e.g., TÜV SÜD, TÜV Rheinland) are some of the well-known Notified Bodies, but they are not the only ones.

Similarly, the terms “approval” or “authorization” in everyday language usually refer to conformity assessment .

How does the IVDR classification differ from the MDR classification?

For in vitro diagnostic medical devices (IVDs), the IVDR (EU) 2017/746 applies. It provides for its own classification system with classes A, B, C, and D.

Unlike the rule-based, product-specific classification of the MDR (Annex VIII), the IVDR uses seven classification rules (Annex VIII IVDR) that focus more on the risk to individuals and public health.

Class A represents the lowest risk (e.g., laboratory aids), while Class D represents the highest (e.g., tests for life-threatening, communicable pathogens in blood donations). Here, too (except for a subset of Class A devices), a Notified Body must be involved.

Software or Apps as a Medical Device (SaMD)

Software can also be a Medical Device. Internationally, this is referred to as SaMD (Software as a Medical Device). Once again, the intended purpose is decisive: An app that merely logs data (e.g., a simple step counter log) is usually not a medical device. An app that makes diagnoses, calculates treatment decisions, or medically interprets measured values, on the other hand, is.

Rule 11 of Annex VIII of the MDR is central to the classification of software. In practice, this often results in a classification of at least Class IIa, and in cases involving decisions that could lead to a serious deterioration in health or surgical interventions, it may also result in Class IIb or III. Software that controls or influences another medical device is classified in the same class as that device. In addition, the internationally harmonized IMDRF Framework for SaMD categorization aids in the reasoning process.

Accessories for Medical Devices

Accessories are items that are not medical devices in themselves but are intended by the manufacturer to enable or support the use of a medical device when used together with it. Accessories are classified independently, meaning they are not automatically placed in the same class as the main product. It undergoes its own risk assessment according to the rules in Annex VIII.

Classification • MDR Annex VIII

The classification determines the entire conformity assessment process

WQS determines which rules from Annex VIII apply to your product, whether the documented intended use supports the selected class, and what information the Notified Body will request.

Frequently Asked Questions

Risk Classification Medical Device Classification Risk Class

What is the risk classification of medical devices under the EU MDR?

According to the EU MDR, medical devices are classified into four risk classes: Class I, IIa, IIb and III. This classification is based on the risk posed by the product when used as intended. The higher the class, the stricter the regulatory requirements for approval, clinical evaluation and market surveillance.

What are the medical device classes under the EU MDR?

The class is determined using the 22 rules in Annex VIII of the MDR, based on intended use, invasiveness, duration of use, active nature, and, where applicable, biological material:

Class I: low risk, non-invasive (e.g., dressings) with the subclasses: Is (sterile), Im (with measuring function), and Ir (reusable surgical instruments).
Class IIa: medium risk, short-term use (e.g., hearing aids)
Class IIb: increased risk, long-term contact or active products (e.g., infusion pumps)
Class III: high risk, life-saving or implantable products (e.g., implants, heart valves)

As the class increases, so do the requirements for clinical data, technical documentation, and the involvement of a Notified Body.

Is my product a medical device?

The decisive factor is the medical intended purpose as defined in Article 2 of the MDR (e.g., diagnosis, treatment, monitoring, or alleviation). If the primary effect is pharmacological, immunological, or metabolic, the product is more likely to be a medicinal product. For borderline cases, WQS offers consultation to help determine the classification.

What determines the risk class of a medical device?

The risk classification of medical devices in the EU is based on the classification rules in Annex VIII of the MDR.
Specific criteria for classification are:

Determination of the intended purpose
Duration of use
Place of use
Reusable surgical instrument
Active medical device
Use of biological material

How does the EU medical device classification compare to the FDA system?

In the EU, classification is rule-based according to Annex VIII of the MDR (Class I, IIa, IIb, and III) and relies on Notified Bodies.
In the US, the FDA classifies products into Class I, II, and III based on risk and equivalence to existing products for device approval (510(k) or PMA).

Why is the intended purpose important for device classification?

The intended purpose is the foundation of the medical device risk classification. According to the MDR and IVDR, it defines the intended medical benefit, the intended use, the intended patient groups and the intended application. This directly determines the risk class (I, IIa, IIb, III) and the required conformity assessment.

How are in vitro diagnostic devices classified under EU regulations?

In vitro diagnostic devices (IVDs) are regulated under EU IVDR 2017/746 and classified into four risk-based categories according to their intended purpose and the associated risks to patients and public health:

Class A – low risk
Class B – moderate risk
Class C – high individual risk or moderate public risk
Class D – high public health risk

Is software or an app a medical device (SaMD)?

Yes, if the software has a medical intended purpose, such as making diagnoses or calculating treatment decisions. Rule 11 of Annex VIII of the MDR is central to the classification, which often results in a classification of at least Class IIa. Apps that are purely for logging or documentation without medical interpretation are generally not medical devices.

Do I need a Notified Body for my product, or is self-certification sufficient?

Class I products (excluding special cases Is/Im/Ir) may be self-certified. For Class Is/Im/Ir as well as Classes IIa, IIb, and III, a Notified Body must be involved. The organizations commonly referred to as “TÜV” are some, but not the only, Notified Bodies.

What happens if I classify my product incorrectly?

Classifying a product in a lower class than it should be can result in a product that is not marketable, recalls, regulatory actions, and liability risks. Classifying a product in a higher class than it should be causes unnecessary effort and costs.
If you’re unsure, WQS can help you determine the correct risk class for your medical device.

What requirements apply to a Class I medical device?

Class I medical devices are generally subject to self-certification by the manufacturer. Key requirements include the preparation of technical documentation, a risk management system, a quality management system (QMS), a self-conducted conformity assessment (without a Notified Body), UDI marking, and an EU Declaration of Conformity.

Which conformity assessment procedure applies under the MDR?

The procedure depends on the class and MDR Annexes IX–XI: Class I is self-certification; Class IIa and above require the involvement of a Notified Body; Class III involves the most extensive scope of testing, including an evaluation of the technical documentation and clinical data.

How does consulting support the classification of medical devices?

Classification determines the entire conformity assessment process. If a product is classified incorrectly, the entire technical documentation will be based on the wrong foundation. Our consulting service classifies products according to the 22 rules in Annex VIII of the MDR and takes into account MDCG 2021-24 Rev. 1.

Further Links

European Parliament & Council of the EU: Regulation (EU) 2017/745 on Medical Devices (MDR), May 5, 2017 – eur-lex.europa.eu
European Parliament & Council of the EU: Regulation (EU) 2017/746 on In-Vitro Diagnostic Medical Devices (IVDR), May 5, 2017 – eur-lex.europa.eu
Dokument der Koordinierungsgruppe für Medizinprodukte (MDCG): MDCG 2021-24 Rev.1 Leitlinien zur Klassifizierung von Medizinprodukten, April 2026 – health.ec.europa.eu