US FDA Medical Device Classification: Risk-Based System and Pathways for Novel Devices

US FDA Medical Device Classification: Risk-Based System

The U.S. Food and Drug Administration (FDA) classifies medical devices into one of three classes (Class I, II, or III) based on the increasing risk they pose to the patient or user. Unlike the rules-based systems used in Europe, the FDA uses a predicate-based system where classification is often determined by finding a legally marketed device that is Substantially Equivalent (SE) to the new product.

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🏥 The Three Device Classes

Class	Risk Level	Required Controls	Premarket Submission	Example
Class I	Low Risk	General Controls	Usually Exempt	Adhesive Bandages
Class II	Medium Risk	Special Controls	510(k) Notification (often)	Endoscopes, Powered Wheelchairs
Class III	High Risk	General + Special Controls	Premarket Approval (PMA)	Pacemakers, Heart Valves

1. Class I (Low Risk) These devices are typically simple in design, such as scalpels and manual stethoscopes. Compliance is primarily ensured through General Controls (e.g., proper manufacturing, labeling, and facility registration). Most Class I devices are exempt from premarket clearance.

2. Class II (Medium Risk) These devices are more complex, but their failure is unlikely to cause serious injury immediately. Special Controls (e.g., performance standards, post-market surveillance) are required in addition to General Controls. Many Class II devices require a 510(k) Pre-market Notification to demonstrate Substantial Equivalence to a predicate device.

3. Class III (High Risk) These devices support or sustain human life, are of substantial importance in preventing health impairment, or pose a potentially unreasonable risk of illness or injury. They require the most rigorous review: Premarket Approval (PMA), which demands extensive scientific data, including clinical trial results, to prove safety and efficacy.

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🔎 Classifying Novel Devices (De Novo and 513(g))

Determining Classification Most devices can be classified by searching the FDA classification database for a Substantially Equivalent predicate device. This search reveals the device's classification, the three-letter Product Code, and the specific regulation number.

513(g) Request for Information If no clear predicate device can be identified, manufacturers can submit a 513(g) Request for Information to the FDA. The agency will evaluate the information and issue a ruling on the device's classification within 60 days. This submission does not grant market approval.

De Novo Classification Request Devices that are entirely new and have no existing classification are automatically considered Class III. If the manufacturer believes the device is not high risk, they may file a De Novo classification request to reclassify it as Class I or Class II. Upon successful De Novo approval, the device can be marketed immediately and serves as a new predicate for future devices.