FDA classifies Medical Devices into 3 risk-based categories, Class I, Class II and Class III wherein Class I devices are considered as low risk devices, and Class III are associated with high risk. The registration requirements and pathway vary with class of device.

The devices can be approved by the CDRH, FDA through any of the various registration pathways. They are listed as:

Class I Medical Devices: The class I devices are usually GMP and 510(k) submission exempt and do not require prior approval from the US FDA to market them in the U.S. Other requirements such as Establishment registration, Device listing, UDI, PMS etc. must be complied by the manufacturer.

Class II Medical devices: Medium risk devices with 510(k) approved predicate devices can opt for 510(k) Pre-market Notification (PMN), also called 510(k) registration. The subject device shall establish Substantial Equivalence (SE) with the identified and claimed predicate devices. This pathway is most widely adapted pathway for registration of devices in the U.S. Manufacturers of medium risk devices with no predicates may request for classification by the US FDA through De-Novo applications.

Class III Medical Devices: High risk class III device manufacturers must submit a Pre-Market Approval (PMA) application to the US FDA. The devices must undergo detailed clinical evaluation and manufacturer must submit detailed safety and efficacy data from clinical studies. The US FDA would carry out QMS inspection as a part of assessment before issuing a Pre-Market Approval for the device.

Based on indications of use, some border line products considered as medical devices in other countries such as, surgical respirators, disinfectants, combination products involve other Agencies such as, Centre for Disease Control (CDC), National Institute for Occupational Safety and Hazards (NIOSH), Environmental Protection Agency (EPA), Centre for Biological Evaluation and Research (CBER), Centre for Drug Evaluation and Research (CDER).