Medical device classifications explained: from Class I to Class III

Medical device classification determines how a product is regulated in Australia, the evidence needed to support its use, and the obligations on manufacturers and suppliers before it can be supplied. This guide is a reference for people new to the sector, including students, junior administrators and early-career professionals.

What is medical device classification?

Classification is a risk-based system that regulates medical devices according to their intended purpose and potential impact on patient safety. In Australia, medical devices are regulated by the Therapeutic Goods Administration (TGA) under the Therapeutic Goods Act 1989.

The class assigned to a device determines:

• the level of regulatory scrutiny required
• the conformity assessment pathway
• the documentation and evidence needed
• post-market monitoring and compliance obligations.

The classes

Australia uses a tiered, risk-based model aligned with international standards. Devices fall into four main classes: Class I (low risk), Class IIa (low to medium), Class IIb (medium to high) and Class III (high). Active implantable medical devices (AIMDs) are classified as Class III.

A device's class depends on its intended clinical use, how long it is used for, how invasive it is, whether it is active or implantable, and whether it interacts with vital organs or systems.

Class I

The lowest-risk devices: generally simple in design, with limited patient interaction and no complex or active mechanism. Examples include reusable surgical instruments, examination gloves and non-powered hospital equipment. Single-use instruments that penetrate the body during surgery are Class IIa or higher.

Most Class I devices do not need TGA conformity assessment certification before inclusion in the Australian Register of Therapeutic Goods (ARTG). The supplier remains responsible for confirming the device meets the Essential Principles for safety, performance and labelling, and for holding the documentation to show it.

Class IIa

A step up in risk, often used in diagnosis, monitoring or short-term treatment. These devices interact more directly with the body and may be invasive for limited periods. Examples include suction equipment, some diagnostic devices and instruments for temporary invasive use. Class IIa devices need evidence of conformity assessment, typically certification from a recognised conformity assessment body.

Class IIb

Medium to high risk devices, often used for longer periods, delivering energy or substances to the body, or supporting important physiological functions. Examples include infusion pumps, long-term surgically invasive devices and powered therapeutic equipment. Assessment places more weight on clinical evidence, risk management and the quality management system.

Class III

The highest risk level. These devices are often implantable, intended for long-term use and may be life-supporting. Examples include implantable cardiac devices and joint replacements. They are subject to the most rigorous assessment, including detailed clinical evaluation, design examination and strict post-market monitoring.

Active implantable medical devices (AIMDs)

Powered devices intended to be implanted in the body, such as pacemakers and neurostimulators. Since 25 November 2021, AIMDs have been classified as Class III, so they follow the same pathway as other Class III devices.

Why classification matters

Classification is more than an administrative step. It affects how long approval may take, the evidence needed before supply, ongoing compliance responsibilities, and post-market surveillance and reporting. For healthcare organisations it also shapes procurement decisions, risk management and clinical governance.

Classification and the ARTG

Before a medical device can be supplied in Australia, it must be included in the ARTG unless an exemption applies. Its classification sets the pathway to inclusion and the documentation required. Manufacturers are responsible for classifying devices correctly and holding appropriate regulatory evidence; incorrect classification can lead to delays, compliance issues or regulatory action.

Recap

This guide is general information, not regulatory advice. Always check the TGA website for current requirements.