Usage Examples
- The submission failed on intended use, so the technological comparison never got reached.
- Different technological characteristics are fine here; we just have to show no new questions.
- There is no valid predicate, so this is a De Novo, not a substantial equivalence argument.
What is Substantial Equivalence (SE)?
Substantial equivalence is the FDA finding that a device has the same intended use as a legally marketed predicate and either the same technological characteristics or different ones that raise no new questions of safety and effectiveness.
Substantial equivalence exists because Congress did not require every device to be proven safe and effective from first principles. For devices comparable to ones already lawfully on the market, the statute allows a comparative showing instead. Substantial equivalence is the legal test that comparison must satisfy, and it is what a 510(k) clearance actually decides.
Substantial equivalence turns on two things in sequence: the device must have the same intended use as the predicate, and it must have either the same technological characteristics or different ones supported by data showing it is as safe and effective and raises no different questions of safety and effectiveness. Substantial equivalence is not a finding that the devices are identical, and it is not an independent finding of safety and effectiveness. It is a finding of comparability to something already marketed.
Substantial equivalence in practice is argued through a predicate comparison table and the testing that closes each identified difference. Intended use is the gate: a difference there ends the analysis regardless of how favourable the performance data is, because there is nothing left to compare against.
Not to be confused with
- 510(k)
- the 510(k) is the submission; substantial equivalence is the finding FDA makes on it. A 510(k) is cleared because FDA found substantial equivalence, so the two are routinely conflated but sit on different sides of the decision.
- PMA approval
- a PMA is an independent demonstration of safety and effectiveness for the device itself. Substantial equivalence is comparative and decides nothing about the predicate's own evidence base. Cleared and approved are different regulatory states.
- De Novo
- De Novo is the route when no valid predicate exists but risks are controllable. It is the alternative to substantial equivalence, not a variant of it, and it creates a classification rather than relying on one.
- Equivalent performance
- matching a predicate's performance specifications does not establish substantial equivalence if the intended use differs, and differing performance does not defeat it if the data show no new questions of safety and effectiveness are raised.
The finding is FDA's, but the submission must contain the material that supports it.
What you must do
- 1Establish that the device has the same intended use as the predicate device21 CFR 807.100(b)
- 2Establish that the predicate has not been removed from the market at the Commissioner's initiative and has not been determined misbranded or adulterated by judicial order21 CFR 807.100(b)
- 3Provide a statement indicating how the device is similar to and different from products of comparable type in commercial distribution, accompanied by data supporting that statement21 CFR 807.87(f)
- 4Include a 510(k) summary under section 807.92 or a 510(k) statement under section 807.9321 CFR 807.87(h)
- 5Submit a new premarket notification where a major change or modification in the intended use of the device is made, since the prior finding no longer covers it21 CFR 807.81(a)(3)(ii)
Common mistakes
Arguing performance before settling intended use
21 CFR 807.100(b) makes same intended use a precondition, not a factor to be balanced. Submissions that lead with favourable bench data against a predicate whose indication differs are answered on the threshold question, and the testing investment is wasted.
Selecting a predicate without checking its market status
the regulation conditions the finding on the predicate not having been removed at the Commissioner's initiative or judged misbranded or adulterated. Predicate selection is a due-diligence step with a specific legal test, not simply a search for the closest similar device.
Reading clearance as an FDA endorsement of safety
substantial equivalence is a comparative finding against a legally marketed device. It does not represent an independent FDA determination that the device is safe and effective, and marketing copy that implies otherwise misstates the regulatory status of the product.
When This Matters
- The submission failed on intended use, so the technological comparison never got reached.
- Different technological characteristics are fine here; we just have to show no new questions.
- There is no valid predicate, so this is a De Novo, not a substantial equivalence argument.
Frequently Asked Questions
No. 21 CFR 807.100(b) allows different technological characteristics, provided the submission contains information demonstrating the device is as safe and effective as the legally marketed device and does not raise different questions of safety and effectiveness. Intended use, by contrast, must be the same.
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