A Class II medical device is one FDA considers moderate risk, where general controls alone are not enough but special controls (such as performance standards or postmarket surveillance) provide reasonable assurance of safety and effectiveness under 21 CFR 860.3. Most Class II devices require a 510(k) premarket notification before marketing.
The Legal Standard
Under 21 CFR 860.3, a device is Class II when general controls by themselves are insufficient to provide reasonable assurance of safety and effectiveness, but there is sufficient information to establish special controls, including performance standards, postmarket surveillance, patient registries, FDA guidance documents, and other appropriate measures, to provide that assurance.
Special Controls, Alongside General Controls
Class II devices carry every general control that applies to Class I (registration, listing, misbranding and adulteration provisions, records and reporting, UDI) plus one or more special controls specific to that device type. Special controls are set at the device-type level in the classification regulation itself, so the exact combination differs from one product code to the next.
The Pathway: 510(k) in Most Cases
Most Class II devices reach the market through a 510(k) premarket notification, which demonstrates the device is substantially equivalent to a legally marketed predicate device. A smaller set of Class II device types are specifically exempted from 510(k) in their own classification regulation, usually with limitations on the exemption, so the applicable classification regulation governs rather than the class designation alone.
FDA Class II vs. EU MDR Class IIa and IIb
FDA Class II and the EU's "Class IIa" or "Class IIb" sound similar but come from separate legal systems and do not translate one-to-one. The EU's Medical Device Regulation, Regulation (EU) 2017/745, classifies devices under its own Annex VIII rules into four classes (Class I, Class IIa, Class IIb, and Class III), based on factors the EU framework defines independently of FDA's system, such as duration and degree of invasiveness. A device can be Class II in the US and IIa in the EU, IIb in the EU, or neither, depending on how each framework's own rules apply to that specific device; one classification cannot be inferred from the other.
Confirming Your Device's Class?
ADB's regulatory team issues a written Classification Determination Memo confirming product code, device class, and regulation number, with rationale.
See 513(g) & Classification Book a Free ConsultFrequently Asked Questions
Does every Class II device need a 510(k)?
No. Most Class II devices need a 510(k), but a subset are specifically exempted from premarket notification in their own classification regulation, usually subject to limitations on the exemption. The classification regulation for the specific product code controls, not the class alone.
What is a special control?
A special control is a device-specific requirement FDA applies in addition to general controls: for example a performance standard, a postmarket surveillance requirement, specific labeling, or an FDA guidance document the device is expected to meet.
Is FDA Class II the same as EU MDR Class IIa or IIb?
No. They come from different legal systems with different rules. FDA Class II is one of three US risk categories under 21 CFR 860.3. EU MDR classifies devices under Regulation (EU) 2017/745, Annex VIII, into four classes (Class I, Class IIa, Class IIb, and Class III), so an EU IIa or IIb device does not map one-to-one onto FDA Class II; each determination has to be made separately against its own framework.