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    Predicate Device

    A legally marketed device used as the comparator in a 510(k) submission.

    Reviewed by Christian Espinosa, Founder, Blue Goat CyberLast reviewed May 5, 2026

    Definition

    A predicate device is a legally marketed device to which a new device is compared in a 510(k) Premarket Notification to support a determination of substantial equivalence.
    What the regulation says
    The FDA, under 21 CFR 807.92(a)(3), requires a medical device manufacturer to identify a predicate device that is legally marketed in the United States when submitting a 510(k) Premarket Notification. The new device must be substantially equivalent to the predicate in terms of intended use, technology, and safety and effectiveness. The EU MDR does not use the term "predicate device" but has analogous provisions for demonstrating conformity, often through comparison to similar devices already on the market.

    What this means in practice

    Selecting an appropriate predicate is one of the most consequential decisions in a 510(k). An ill-chosen predicate can trigger a Not Substantially Equivalent (NSE) determination, requiring a De Novo or PMA pathway.

    Examples

    • A company developing a new surgical Stapler identifies an older model of surgical stapler from a different manufacturer that already has 510(k) clearance, using it as a predicate.
    • A manufacturer of a novel diagnostic imaging system uses a previously cleared MRI machine as a predicate, demonstrating similar intended use and fundamental scientific technology.
    • A startup creating an AI-powered diagnostic software lists a cleared, non-AI diagnostic software with the same intended use as its predicate to establish substantial equivalence in basic function, then addresses the AI-specific aspects.
    Common pitfalls
    • •Choosing a predicate device with different indications for use than the new device can lead to a finding of "Not Substantially Equivalent."
    • •Selecting a predicate that has been recalled or has known safety issues can jeopardize the 510(k) submission.
    • •Failing to adequately document the similarities and differences between the new device and the predicate can result in submission delays or rejection.
    • •Relying on a predicate device for which there is insufficient publicly available information can make substantial equivalence difficult to prove.
    • •Not considering the technological characteristics and performance data of the predicate can lead to an inappropriate comparison.

    Frequently asked questions

    A device is legally marketed if it was in commercial distribution before May 28, 1976 (preamendments device), or has been reclassified from Class III to Class II or I, or has been found substantially equivalent through the 510(k) process, or has been approved through a PMA or granted through a De Novo classification request.

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    Primary references

    3 sources
    Link health: 3 verified· last checked 2026-06-20
    FDA·2European Commission·1
    1. 1
      Best Practices for Selecting a Predicate Device
      Verified
      FDAfda.gov
    2. 2
      FDA - Medical Devices
      Verified
      FDAfda.gov
    3. 3
      European Commission - Medical Devices
      Verified
      European Commissionhealth.ec.europa.eu

    Inline markers like [1] jump to the matching reference above.