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). The decision follows the flowcharts in FDA's 2017 guidance 'Deciding When to Submit a 510(k) for a Change to an Existing Device' and its software-specific companion. Supporting verification and validation should sit with the rationale in the quality system records. FDA may review these during inspections and disagree with the conclusion.

Why it matters

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.

Common pitfalls

•Failing to provide objective evidence and a robust scientific rationale for the decision is a common pitfall.
•Inaccurately assessing the impact of a change on device safety or effectiveness can lead to regulatory non-compliance.
•Not obtaining necessary expert reviews or management approvals for the Letter to File can be a critical error.
•Treating a Letter to File as a routine administrative task rather than a critical regulatory decision is a common mistake.
•Neglecting to update relevant risk management files (e.g., in accordance with ISO 14971:2019) after a change is a significant oversight.

Sources

Deciding When to Submit a 510(k) for a Change · FDA
RAPS Regulatory Focus · RAPS
FDA - Medical Devices · FDA

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Common comparison patterns

Regulatory pathway choice - 510(k) vs PMA, 510(k) vs De Novo, Abbreviated vs Special 510(k).
Quality systems - QSR vs ISO 13485, QMSR vs QSR.
Software classification - SaMD vs SiMD, Locked vs adaptive AI.
EU frameworks - MDR vs IVDR, CE Mark vs UKCA.
Cybersecurity artifacts - SPDX vs CycloneDX SBOM, CVE vs CVSS.
Post-market actions - Recall vs field action, Removal vs correction.

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MedTech Terms is a vendor-neutral community resource sponsored by Blue Goat Cyber. Definitions are written for educational use and are not legal or regulatory advice.