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Substantial Equivalence Explained

Substantial equivalence (SE) is the standard a 510(k) submission must meet. It is the core legal concept of the 510(k) pathway.

The statutory standard​

Under FD&C Act § 513(i), a device is substantially equivalent to a predicate if it:

  1. Has the same intended use as the predicate; and
  2. Has the same technological characteristics as the predicate; OR
    • Has different technological characteristics that do not raise different questions of safety and effectiveness; and
    • The information in the submission demonstrates that the device is at least as safe and effective as the legally marketed device.

Intended use comparison​

Same intended use: The new device and the predicate must have the same general intended use — they don't need to have identical intended uses, but the new device's intended use must fall within the same general category.

Different intended use: If the new device has a different intended use from the predicate, the device is not substantially equivalent — regardless of how similar the technology is.

Technological characteristics comparison​

If intended use is the same, FDA then evaluates technological characteristics:

Same technological characteristics: FDA typically finds SE with limited additional data.

Different technological characteristics: FDA evaluates whether the differences:

  1. Raise new questions of safety and effectiveness — if yes, NSE is likely
  2. If no new questions are raised, FDA evaluates whether the device is at least as safe and effective as the predicate, typically through:
    • Bench testing (performance data)
    • Biocompatibility data (ISO 10993)
    • Software documentation
    • Sterility/packaging validation
    • Clinical data (if non-clinical data is insufficient)

The SE decision tree​

New device
    │
    ▼
Same intended use as predicate?
    │
    ├── No ─────────────────────────── → NSE
    │
    └── Yes
           │
           ▼
    Same technological characteristics?
           │
           ├── Yes ─────────────────── → SE (with appropriate data)
           │
           └── No
                  │
                  ▼
           Do differences raise new safety/effectiveness questions?
                  │
                  ├── Yes ─────────────── → NSE (likely)
                  │
                  └── No
                         │
                         ▼
                  Data demonstrates at least as safe/effective as predicate?
                         │
                         ├── Yes ──────── → SE
                         └── No ─────────── → NSE

What SE is not​

Substantial equivalence does not mean:

  • The device is identical to the predicate
  • The device is as good as the predicate in every way
  • The device meets an absolute safety/effectiveness threshold

It is a comparative standard — the device must be at least as safe and effective as the predicate.

Official resources​