In the USA, medical devices are regulated by the Food and Drug Administration (FDA) with an aim to ensure safety and effectiveness of the devices. The Center for Devices and Radiological Health (CDRH) is an FDA component and looks after this program.
Medical devices are classified into three categories based on the associated risk, namely: Class I, II and III. Class I devices will have least associated risk while class III devices will have the highest associated risk. Accordingly, regulatory control surges from Class I devices to Class III devices.
With respect to that, most of Class I devices are exempted from 510(k) premarket notification submission, while most of Class II devices are submitted for premarket notification. On the other hand, Class III devices need to go through the Premarket Approval Application (PMA) and other class III devices, which are exempted from PMA must submit a 510(k) notification to FDA.