The U.S. Food and Drug Administration (FDA) approves medical devices along with many other products. During the approval process, the FDA looks at a medical device’s structure, the current research on its risks and benefits, and other information in order to decide whether or not to approve the device or specific uses.
The first step in getting a medical device approved is to file a “Premarket Notification,” also known as a “PMN” or a “510(k),” after the section of the Federal Food, Drug, and Cosmetics Act that governs the premarket notification procedure. Then, the manufacturer must wait at least 90 days while the FDA reviews the Premarket Notification.
When it reviews the Premarket Notification, the FDA classifies the medical device it describes into one of three classes.
Class I: “Low-Risk” Devices
Class I devices are considered “low-risk” because they are not designed to treat potentially fatal conditions and are unlikely to cause life-threatening harm if misused. Class I devices do not have to be approved by the FDA, but they are governed by other rules, like those related to misbranding, adulteration, and required information that must be given to customers.
Class I devices are often available over the counter. Dental floss, latex gloves, and adhesive bandages are examples of Class I devices.
Class II: “Medium-Risk” and 501(k) Devices
Class II devices are considered “medium-risk.” They are usually not intended to treat potentially fatal conditions, but they can cause harm if misused. Powered wheelchairs, infusion pumps, and dental amalgam used in fillings are all currently considered Class I devices.
A device is also eligible for Class II if it is “substantially similar” to a device marketed before May 28, 1976. If the FDA finds a Premarket Notification describes a “substantially similar” device, it may allow the manufacturer to start selling the device without going through the rest of the formal FDA approval process. Devices that get to market in this way are often said to have passed the “510(k) process.” They cannot be marketed as “FDA-approved,” but they can be referred to as “cleared” or “510(k) cleared.”
Class III: “High-Risk” and “Premarket Approval” Devices
Class III devices are also known as “high-risk” devices. These are medical devices that are intended to support or sustain life, are of “substantial importance in preventing impairment of human health,” or that present a high risk of injury or death if used improperly. In practice, Class III devices are almost always either devices implanted in the body, devices for saving lives, or both. For instance, artificial hearts and automated external defibrillators (AEDs) are both Class III devices.
A Class III device is not eligible for 510(k) clearance. Instead, its manufacturer must follow the Premarket Approval (PMA) process. If it passes, it may be referred to as “FDA-approved” for certain purposes.
510(k) Approval Process
The 510(k) approval process begins just like the approval process for any other medical device: with the filing of a Premarket Notification (PMN), also called a “510(k) form.” The manufacturer must wait at least 90 days after filing the PMN before taking any more actions to bring the device to market. During this 90-day wait, the FDA examines the PMN and decides if the device falls in Class II and if it is “substantially similar” to a device already on the market.
In making this determination, the FDA can consider technological advancements. For instance, a device for cauterizing wounds with a laser may be given 510(k) clearance if its risks and benefits are “substantially similar” to an already-approved device that cauterizes wounds using heated wires. Even though the technology is different, the laser device might be granted 510(k) clearance if its purpose, use, risks, and benefits are substantially similar to the purpose, use, risks, and benefits of the similar heated-wire device.
The FDA is required by law to compare the device listed in the PMN to a legally-marketed device already being sold, if a similar one exists. How the devices are compared depends on each device’s particular characteristics, but it usually involves a comparison of the physical properties of each device and the way it performs.
Sometimes, standards set by other regulatory bodies are used to compare devices. For instance, if the FDA is examining a new kind of glove designed to be worn in surgery, it might use the ASTM International standards for protective gloves as a guide to help it decide whether the new glove offers a “substantially similar” level of protection to gloves already on the market. It will also use these standards to decide whether the glove can perform adequately in surgery, since the ASTM International standards set minimum requirements for things like stretchability, leak risks, and use of non-toxic materials – all things that are important in a glove designed to be worn for protection and health reasons.
Some devices are also evaluated at this stage based on how they have actually performed in real-world conditions, compared to similar devices that are already on the market. Although these tests aren’t required to file a PMN or to get 510(k) clearance, many manufacturers will perform them in order to make sure their product works as intended and will include the information from their tests in the PMN. The FDA generally does not test medical devices itself.
If the FDA finds that the device described in the PMN is “substantially similar” to a device already on the market, it may allow the manufacturer to start selling the device without requiring more information or testing. This grant of permission to go to market is known as a “510(k) clearance.” With a 510(k) clearance, the manufacturer may go straight to market, without first passing through the Premarket Approval (PMA) process that requires clinical trials and other stringent studies of the device’s uses, safety, and possible risks.
Because the 510(k) clearance allows the manufacturer to skip the PMA process, devices given 510(k) clearance are by definition not “approved” by the FDA, and manufacturers may not refer to them as “FDA-approved.” However, they are allowed to legally be sold in the U.S.