Medical devices are not approved through one process. Regulators sort them by risk, and the class a device lands in determines nearly everything that follows.
Risk classification comes first
Devices are grouped by how much harm a failure could cause. A bandage sits at one end of the scale, an implanted device that sustains life at the other.
Classification considers how invasive the device is, how long it contacts the body, and whether the user can detect a malfunction before harm occurs.
Everything downstream follows from this placement, so manufacturers and regulators sometimes disagree about which class a novel product belongs in.
Low-risk devices face general controls
The lowest class is largely governed by baseline requirements: proper labelling, manufacturing quality standards, registration of the facility and reporting of adverse events.
Most of these products do not require a submission demonstrating clinical performance before they can be sold, because the failure modes are well understood.
The controls are not absent. They are general rather than product-specific, applying the same expectations across a wide range of familiar items.
Middle-risk devices lean on comparison
For the intermediate class, a common route is demonstrating that the new device is substantially equivalent to one already legally marketed.
The manufacturer shows the device has the same intended use and comparable technological characteristics, and that any differences do not raise new safety questions.
This pathway is faster than a full clinical review, which is both its purpose and the reason it attracts sustained criticism from researchers who study device failures.
High-risk devices require evidence of their own
The highest class generally cannot rely on comparison. The manufacturer must submit data demonstrating that the device is safe and effective for its stated use.
That usually means clinical study data, alongside detailed engineering, materials and manufacturing information reviewed by the regulator directly.
Review at this level takes considerably longer, which is one reason implantable and life-sustaining technologies reach the market more slowly than consumer health products.
Oversight continues after clearance
Clearance is not the end. Manufacturers must report certain malfunctions and injuries, and regulators track these reports for patterns that trials were too small to reveal.
Post-market studies are sometimes required as a condition of clearance, and findings can lead to labelling changes, restrictions or removal from the market.
Rules differ by country and change over time, so anyone evaluating a specific device should consult current guidance from the relevant national authority.