The FDA classifies medical devices into Class I (low risk), Class II (moderate risk), and Class III (high risk) based on potential harm. Regulatory requirements increase with risk, from general controls to 510(k) clearance or PMA.
Before you can prepare a 510(k), you must identify your device’s classification and select an appropriate predicate. The FDA groups approximately 1 ,700 generic medical device types into 16 panels (e.g., cardiovascular, orthopedic) and assigns each type to Class I, Class II or Class III according to risk. Class I devices have the lowest risk and are subject only to general controls such as establishment registration, device listing and good manufacturing practices; most Class I devices are exempt from 510(k) requirements. Class II devices pose moderate risk and require both general controls and special controls; most Class II devices need a 510(k). Class III devices sustain or support life or present a potential unreasonable risk and require a PMA unless down‑classified via the De Novo program.
To classify your device, define its intended use and technological characteristics. Search the FDA’s Product Classification database for a product code corresponding to your device. Product codes link to regulation numbers, class and exemptions. If multiple codes apply, choose the one that best represents the primary intended use. Knowing the product code not only determines whether a 510(k) is required but also guides the selection of predicate devices.
When selecting a predicate device, the key is to demonstrate substantial equivalence. A predicate may be any legally marketed device: one cleared via 510(k), a pre‑amendment device, a device down‑classified from Class III, or a device exempt from 510(k). Your new device must have the same intended use and either the same technological characteristics or different technological characteristics that do not raise new questions of safety or effectiveness. Differences must be justified with data showing they do not introduce new risks. In some cases, you may designate a primary predicate for intended use and cite reference devices to support specific technological features. When multiple predicates are used, clearly explain how the combination supports substantial equivalence.
Consider the following tips for predicate selection:
Selecting the correct classification and predicate sets the stage for your testing plan, documentation requirements and regulatory timeline. A mismatched predicate or incorrect classification can lead to additional testing requests or an NSE decision. If you are uncertain about classification or predicate selection, consider submitting a pre‑submission request to obtain FDA feedback.
