There are 3 classes of devices:
- Class 1: low-risk devices (e.g. toothbrushes, dental floss, band aids). Class 1 devices are subject to minimal regulatory controls.
- Class 2: moderate- risk devices (e.g. powered wheelchairs). Class 2 devices require greater regulatory controls.
- Class 3: highest-risk devices (e.g. metal on metal hips, replacement heart valves). Class 3 devices are supposed to undergo the highest level of regulatory control known as Premarket Approval, or PMA.
According to the FDA, Premarket Approval (PMA) requires manufacturers to submit an application if they intend to market any new products containing new materials or differing in design from products already on the market. A PMA submission must provide valid scientific evidence collected from human clinical trials showing the device is safe and effective for its intended use.
However, many class 3 devices do not undergo PMA. They are cleared through the 510 (k) process, claiming substantial equivalence to preamendment devices, or comparable devices already on the market. Unfortunately, this allows companies a means of avoidance in testing their products for safety and effectiveness before releasing them on the market.