Class IIa medical devices: definition, examples, and requirements

Class IIa medical devices are among the most common products on the European market. This article explains which products fall into this class, which classification rules are relevant, and what regulatory consequences this has.

1. Definition: What is a Class IIa medical device?

Class IIa medical devices are products with a medium risk potential according to the EU Medical Device Regulation (MDR) 2017/745. They require the involvement of a notified body in the conformity assessment procedure. Typical examples are diagnostic devices, short-term invasive products, or active therapeutic products for energy delivery, provided that this energy does not pose a potential hazard.

Classification in the classification system The MDR distinguishes between four risk classes:

Class	Risk potential	Examples
I	Low	Bandages, crutches
II	Medium	Blood pressure monitors, disposable catheters
IIb	Increased	Ventilators, X-ray machines
III	High	Pacemakers, hip implants

Important: Classification is based on the manufacturer’s intended purpose, not on technical complexity or price.

2. Examples: Which products belong to class IIa?

Typical Class IIa products by category

Category	Examples
Diagnostic devices	Blood pressure monitors, clinical thermometers
Short-term invasive products	Disposable catheters (< 60 min.), cannulas, tracheal tubes
Active therapeutic devices	TENS devices, ultrasound therapy devices
Contact lenses	Daily disposable lenses, soft contact lenses (not long-term)
Wound care	Wound dressings (non-absorbable, not for chronic wounds)
Software	DiGA for therapy support (without diagnosis of serious illnesses)

Example: contact lenses

• Daily disposable lenses → Class IIa
• Long-term contact lenses (> 30 days) → Class IIb

3. Classification rules: Which rules lead to Class IIa?

Classification is based on Annex VIII of the MDR. The following rules can lead to Class IIa:

Overview of relevant rules

Rule	Product type	Class IIa if…
5	Non-invasive	Intended for the storage/transport of blood, body fluids, or tissue
6	Non-invasive	Intended to alter the composition of blood/body fluids by filtration, centrifugation, or gas/heat exchange
7	Invasive (body orifices)	Intended for short-term use (< 60 min) OR long-term use in the oral cavity/ear canal/nasal cavity
9	Active therapeutic	Energy is delivered in a non-potentially dangerous manner
10	Actively diagnostic	Intended for direct diagnosis/monitoring of vital bodily functions (without immediate danger)
11	Software	Information for therapy decisions, if errors do not cause serious deterioration
12	Drug administration	Administration is carried out in a manner that is not potentially dangerous.

Special feature: Rule 11 (software as a medical device)

Software is classified according to Rule 11. Classification depends on

• the type of information provided,
• decisions based on it, and
• the consequences of misinformation.

4. Decision tree: Is my product Class IIa?

The following decision tree guides you through the most important classification paths:

This decision tree covers the most common cases. However, it does not fully reflect all 22 classification rules. In case of doubt, a detailed review based on Annex VIII MDR is required.

5. Consequences: What does Class IIa mean in concrete terms?

The classification has a direct impact on the regulatory burden: a. Requirements in the “class comparison”

Aspect	Class I	Class IIa	Class IIb	Class III
Notified body required	No	Yes	Yes	Yes
Conformity assessment	Annex IV	Annex IX (Chapters I+III) or XI Section 10 or Section 18	Annex IX (Chapters I+III) or X+XI	Annex IX or X+XI Part A
TD testing by notified body	No	Random sampling	Random sampling	Complete
PSUR frequency	Not required	At least every 2 years	At least annually	At least annually
Clinical examination	Rarely	Mostly no	More frequent	Often required
Expert panel	No	No	Only implantable	Yes (new products)
Instructions for use	Can be omitted**	Can be omitted**	Always required	Always required
PRRC required	Yes	Yes	Yes	Yes
UDI requirement	Yes	Yes	Yes	Yes
EUDAMED registration	Yes	Yes	Yes	Yes

*Exception: Classes Is, Im, Ir require a notified body
**If safe use is guaranteed without instructions for use (Annex I, Section 23.1)

b. Conformity assessment procedures for Class IIa

There are two options for Class IIa:

1. Annex IX, Chapters I + III: QMS assessment + TD testing on a random basis
2. Annex XI, Section 10 or Section 18: Product testing

c. Sampling of technical documentation

For Class IIa, the notified body does not check every piece of technical documentation in full. Instead, a risk-based sample selection is carried out:

Selection criteria:

• Product categories ( Generic Device Groups )
• At least one product per category
• New products are prioritized
• Products with incidents are prioritized
• Sample size increases with portfolio size

Monitoring audits: Additional samples are checked during annual audits.

d. PSUR: Periodic Safety Update Report

Manufacturers of Class IIa devices must prepare a PSUR.

• Frequency: At least every 2 years (for Class IIb/III: annually)
• Content: Summary of all PMS data, benefit-risk assessment
• Template: from the Notified Body

6. What does the classification not affect?

Many requirements apply regardless of class:

Requirement	Applies to all classes?
General safety and performance requirements (Annex I)	✓ Yes
Risk management according to ISO 14971	✓ Yes
Quality management system	✓ Yes
Post-market surveillance (basic obligation)	✓ Yes
Technical documentation (structure according to Annex II/III)	✓ Yes
Vigilance reporting obligations	✓ Yes
Product liability	✓ Yes

Conclusion for manufacturers

The classification primarily determines the scope of the external audit by the notified body – not the internal quality effort. Even Class I products require a complete QMS and compliant technical documentation.

7. International perspective

Does Class IIa also apply outside the EU?

No. The MDR classification only applies in the European Economic Area (EU + Iceland, Liechtenstein, Norway) and Switzerland. Other markets have their own systems:

Market	System	Comparability
USA (FDA)	Class I, II, III	Not directly comparable
China (NMPA)	Class I, II, III	Own rules
Japan (PMDA)	Class I–IV	Four classes

Example: A Class IIa product in the EU may be Class II or Class III in the US.

8. Transition periods: What applies to existing products?

Some products are classified higher under the MDR than under the previous MDD:

Examples of upgrades:

• Reusable surgical instruments: I → Ir (with notified body)
• Certain software: I → IIa or higher
• Central venous catheters for short-term use: IIa → III

9. Can the classification be influenced?

The classification is based on the intended purpose, which is determined by the manufacturer. Legitimate strategies

Strategy	Example
Limit the range of functions	Software only displays instead of analyzing → lower class
Limit duration of use	Short-term instead of long-term invasive → lower class
Specify indication	Exclusion of certain patient groups
Product division	Separation into several products with different classes

10. Summary

Class IIa medical devices:

• These are products with medium risk potential.
• The involvement of a notified body is required.
• The technical documentation is reviewed on a random basis.
• A PSUR must be prepared at least every 2 years.
• The preparation of instructions for use may not be necessary in some circumstances.

Most important classification rules: 5, 6, 7, 9, 10, 11, 12

Crucial: The intended purpose determines the class – not the technology.