The PMA preempts. The 510(k) doesn't.

Two devices can do almost the same clinical job, clear FDA review in the same year, and end up on opposite sides of a line that has nothing to do with either device’s safety record: one manufacturer can have a state tort claim thrown out before discovery starts, and the other cannot, because of which premarket pathway the device went through. That line is federal preemption, and the statute that draws it reads the same for every device. The courts have not applied it the same way to every pathway.

The statute, and what it actually bars

21 U.S.C. § 360k(a) is short: no state may establish or continue in effect, with respect to a device, a requirement that is both different from, or in addition to a federal requirement applicable to that device, and that relates to safety or effectiveness or another matter the federal requirement covers. Section (b) lets a state petition FDA for an exemption from that bar; it is rarely used and nothing turns on it here. What matters for every device company is what counts as a federal “requirement” specific enough to trigger the first clause — and the Supreme Court has answered that question twice, with two different results, for two different pathways.

Lohr: 510(k) asks the wrong question to count

In Medtronic, Inc. v. Lohr (1996), the Court held that a 510(k) clearance does not impose a device-specific federal requirement at all. Section 510(k) review asks whether a device is substantially equivalent to a device already on the market before 1976 — it does not ask FDA to independently weigh that device’s own safety and effectiveness the way a PMA review does. A process built around resemblance, not an independent finding, leaves nothing specific enough to preempt. The result: a state tort claim over a 510(k)-cleared device’s design or warnings is not, as a rule, barred by § 360k(a).

Riegel: PMA approval is the requirement

Riegel v. Medtronic, Inc. (2008) drew the opposite line for the other pathway. A PMA review weighs a specific device’s own safety and effectiveness against FDA’s own standards before approval — and that approval, with its conditions, is itself a federal requirement specific to that device. A state claim asking a jury to hold the device to a different design, different labeling, or a different manufacturing standard than what FDA approved is a requirement “different from, or in addition to” the federal one. Riegel held it preempted.

The Court left one door open even for PMA devices: preemption, it wrote, “does not prevent a State from providing a damages remedy for claims premised on a violation of FDA regulations” — a claim that parallels the federal requirement rather than adding to it. Riegel itself did not have to decide how far that door opens; lower courts have split since on how closely a state claim has to track an actual federal violation to count as parallel rather than additional.

De Novo: no Supreme Court answer yet

Neither Lohr nor Riegel addressed the pathway that has grown the most since both were decided. De Novo classification sits between the two in the regulatory scheme — it reaches a device with no predicate, grounded in FDA-issued special controls, without PMA’s full premarket-approval review. For most of three decades, courts read Lohr broadly enough to treat any device outside the PMA track, De Novo included, as unpreempted by default. In July 2024, a federal district court in Louisiana broke from that default: in Dickson v. Dexcom, Inc., the court held that § 360k(a) preempted safety and effectiveness claims against a Class II continuous glucose monitor cleared through De Novo, reasoning that the device-specific special controls FDA built into its own classification order were themselves a federal requirement under Riegel’s test — not a 510(k)-style resemblance finding under Lohr’s. It is one district court decision, not an appellate holding, and not binding outside its own docket, but other courts have since cited it for the same proposition.

The practice

None of this changes what a classification order, a clearance letter, or a PMA approval says about a device’s market status — openFDA’s own clearance and classification records carry no field for preemption at all, because preemption is not a determination FDA makes; it is a consequence courts draw from the record FDA already made. A pathway decision that looks purely like a cost-and-timeline tradeoff on a regulatory strategy memo carries a second, separate consequence that shows up only if the device is ever sued, decided by a different body, under a different body of law, years after the clearance letter is filed away. Whether a specific product’s own facts fall on one side of that line or the other is a question for litigation counsel working that product’s own record — this is a description of how the doctrine is built and where it currently stops, regulatory intelligence and method, never regulatory or legal advice about any specific device’s litigation exposure.