Walk through a hospital and most of the devices you see, from infusion pumps to blood-glucose meters to surgical staplers, reached the market the same way: a 510(k) premarket notification. The number comes from section 510(k) of the Federal Food, Drug, and Cosmetic Act, and the mechanic is simpler than the name suggests. Instead of proving a device is safe and effective from scratch, the manufacturer shows the FDA that the device is substantially equivalent to a device already legally on the market. The agency reviews the comparison and, if it agrees, sends a clearance letter. The legal home for the requirement is the regulation at 21 CFR 807.81.

That regulation is precise about when a notification is required and how early it must arrive. It states that a manufacturer must file with the FDA at least 90 days before introducing a device into interstate commerce for commercial distribution when the device is being marketed for the first time and is not of the same type as, or substantially equivalent to, a device already in distribution. In other words, the 90-day window is built into the rule itself, and the trigger is the act of bringing a new or changed device to market.

"each person who is required to register his establishment pursuant to § 807.20 must submit a premarket notification submission to the Food and Drug Administration at least 90 days before he proposes to begin the introduction or delivery for introduction into interstate commerce for commercial distribution of a device intended for human use."— 21 CFR 807.81, source

Clearance is not the same as approval

The vocabulary matters here, because the FDA uses two different words on purpose. A device that goes through 510(k) is cleared; a device that goes through the more demanding premarket approval (PMA) pathway is approved. Clearance means the FDA has determined the new device is substantially equivalent to a predicate, so it can be legally marketed. It does not mean the agency independently established the device's own safety and effectiveness through original clinical evidence the way a PMA does. The 510(k) bargain is that a predicate already cleared or approved carries the safety-and-effectiveness reasoning forward, and the new device rides on that equivalence.

What does the submission actually contain? The regulation at 21 CFR 807.87 lists the required elements: the device name, including the trade name and the common or classification name; the establishment registration number where applicable; the class the device has been placed in under section 513 of the act; and the proposed labeling and a description of the device, among other items. The heart of the package is the substantial-equivalence comparison, where the submitter identifies the predicate device and shows the new device has the same intended use and either the same technological characteristics or different characteristics that do not raise new questions of safety and effectiveness.

How common is the pathway, and what a clearance looks like

The 510(k) route is the dominant way devices reach the U.S. market. The FDA's openFDA 510(k) dataset records more than 173,000 decisions marked 'Substantially Equivalent,' each one a cleared device with its own K-number, applicant, product code, and advisory-committee panel. A single record makes the structure concrete. Clearance K241907, decided October 2, 2024, cleared the 'Anovo Surgical System (model 6N)' submitted by Momentis Surgical, Ltd., under product code QNM in the General and Plastic Surgery panel. Another, K240526, cleared Stryker Instruments' 'POWEReam Xia/Serrato' on April 29, 2024, under the Orthopedic panel. Each carries a decision of substantial equivalence, the formal output of the pathway.

Those product codes are not decoration. Each one ties the device to a regulation number and a device class in the FDA's classification database, which is what tells a manufacturer up front whether a 510(k) is even the right submission. A device whose product code maps to Class II almost always needs a 510(k); a Class I device may be exempt; a Class III device generally needs the PMA pathway instead. The classification lookup is therefore step one, and the 510(k) is what follows for the large middle tier of devices.

It is also worth being clear about what a 510(k) clearance does and does not establish. It establishes that the FDA found the device substantially equivalent to a named predicate and that the device may be legally marketed in the United States. It does not establish that the device is superior to alternatives, that it carries no risk, or that it underwent the original premarket clinical proof a PMA demands. The clearance letter is a regulatory permission grounded in equivalence, and the public record, K-number, applicant, product code, decision date, and panel, is exactly what the openFDA database publishes for each one.

Traditional, Special, and Abbreviated 510(k)s

Not every 510(k) looks the same, and the openFDA records label the variation in a field called clearance type. The two cleared devices above, K241907 and K240526, are both marked 'Traditional,' the default route used when a device is new to a submitter or has changed in ways that need a full substantial-equivalence review. The FDA also recognizes a 'Special' 510(k), used when a manufacturer modifies its own already-cleared device and the change can be verified against established design controls, and an 'Abbreviated' 510(k), which leans on FDA-recognized consensus standards and guidance to streamline the comparison. All three end in the same place, a substantial-equivalence determination and a clearance, but they differ in how the equivalence is demonstrated. The clearance-type field in each record tells you which route a given device took.

There is one more structural feature worth naming: the third-party review program. The openFDA records carry a 'third_party_flag,' and for many lower-risk device types the FDA allows an accredited third-party organization to conduct the initial 510(k) review and forward a recommendation to the agency. The FDA still makes the final clearance decision, but the program is designed to move appropriate submissions through faster. For the two example clearances, the flag is set to 'N,' meaning the agency reviewed them directly. Reading these fields, clearance type and third-party flag, alongside the K-number and product code, gives a fuller picture of exactly how a device earned its clearance, all of it from the public record.

For a reader trying to make sense of a device's regulatory status, the practical takeaways are these. 'FDA cleared' on a label points to the 510(k) pathway and a substantial-equivalence determination. The 90-day premarket window and the substantial-equivalence requirement both come straight from 21 CFR Part 807. And the entire history of cleared devices, more than 173,000 substantially-equivalent decisions and counting, sits in a public dataset anyone can query by K-number or product code.