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    Letter to File

    Internal documentation justifying that a device change does not require a new 510(k) submission.

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

    Definition

    A Letter to File is a manufacturer-prepared rationale, retained in the device's design history, explaining why a change does not significantly affect safety or effectiveness and therefore does not trigger a new 510(k).

    What this means in practice

    FDA's 'Deciding When to Submit a 510(k) for a Change' guidance provides flowcharts. LTFs are scrutinized during inspections; weak rationales are a common Form 483 finding.

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    Primary references

    3 sources
    Link health: 3 verified· last checked 2026-05-09
    FDA·2RAPS·1
    1. 1
      Deciding When to Submit a 510(k) for a Change
      Verified
      FDAfda.gov
    2. 2
      RAPS Regulatory Focus
      Verified
      RAPSraps.org
    3. 3
      FDA - Medical Devices
      Verified
      FDAfda.gov

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