Introduction

In the rapidly evolving medical device landscape, software plays a central role—from embedded firmware to standalone applications (i.e., Software as a Medical Device (SaMD): Clinical Evaluation). Documentation of that software is a critical component of regulatory compliance for manufacturers seeking U.S. market access under the jurisdiction of the U.S. Food & Drug Administration (FDA). This article outlines key requirements and best practices for software documentation for medical devices in the United States, helping device manufacturers align with FDA expectations and avoid regulatory missteps.

 

 

 

Regulatory Framework & Scope

 

 

  • The FDA issued its most recent guidance titled Content of Premarket Submissions for Device Software Functions: Guidance for Industry and Food and Drug Administration Staff (June 14, 2023). This supersedes previous guidance from 2005 regarding software contained in medical devices. 

  • The guidance clarifies that software functions that meet the definition of a “device” under Section 201(h) of the Federal Food, Drug, and Cosmetic Act (FD&C Act) are subject to FDA review. 

  • The risk-based approach applies: software may be subject to pre-market review (such as 510(k), De Novo, or PMA) or fall under enforcement discretion depending on the function. 

  • While this article focuses on U.S. requirements, it is worth noting that international frameworks (like the International Medical Device Regulators Forum — IMDRF) influence global harmonisation of software as a medical device (SaMD). 

 

 

 

 

Why Robust Software Documentation Matters

 

 

  • Comprehensive software documentation demonstrates traceability, design control, risk mitigation and verification/validation evidence—core elements of compliance with ISO 13485, IEC 62304 (for software lifecycle), and FDA’s Quality System Regulation (QSR). 

  • Poor documentation or inadequate software process evidence may lead to submission delays, non-conformities during inspections, or even regulatory actions.

  • Well-structured documentation supports cross-functional collaboration (software engineering, regulatory, quality, clinical) and aids in future modifications, maintenance, and audit readiness.

 

 

 

 

Core Software Documentation Elements

According to the 2023 FDA guidance and best practices, your software documentation should include (but is not limited to) the following:

 

1. Software Requirements Specification (SRS)

 

 

  • Describes what the software will do (functional requirements) and how it interacts with the system and users. 

  • Should address user interface, data inputs/outputs, performance, safety, cybersecurity, interoperability, and error conditions.

  • For SaMD or connected devices, include clinical/user context and usability considerations.

 

2. Software Design Specification (SDS)

 

 

  • Defines how the requirements in the SRS will be implemented in terms of architecture, modules, interfaces, data structures, algorithms, and hardware/software mapping. 

  • Ensures traceability from requirements through design, implementation, verification.

 

3. Verification and Validation (V&V) Documentation

 

 

  • Verification: evidence that each requirement has been implemented correctly (e.g., unit tests, integration tests).

  • Validation: evidence that the software meets user needs and intended uses in its real-world environment (e.g., usability testing, clinical performance).

  • The FDA’s “General Principles of Software Validation” guidance applies. 

  • Maintain test plans, test protocols, test reports, coverage metrics.

 

4. Risk Management Documentation

 

 

  • A software risk analysis that identifies hazards, hazardous situations, causes, and software mitigations (single-fault conditions, residual risk).

  • Tie risk controls into software design and verification evidence.

  • Documentation must align with your device risk management file under ISO 14971.

 

5. Traceability Matrix

 

 

  • Demonstrates mapping between user requirements, software requirements, design elements, test cases, and risk controls.

  • Facilitates auditability and review by regulators.

 

6. Configuration Management & Change Control

 

 

  • Documents software versioning, build environment, baselining, release notes, change history.

  • Important for maintenance, post-market changes, and demonstrating control of modifications.

 

7. Software Maintenance & Decommissioning

 

 

  • Documentation on how software will be maintained, updated (patches, bug fixes), and eventually decommissioned.

  • Especially relevant for connected devices and SaMD. 

 

8. Cybersecurity Documentation (If Applicable)

 

 

  • Include cybersecurity risk analysis, mitigation strategy, vulnerability management, secure software development lifecycle (SSDLC) evidence.

  • This is increasingly scrutinised by the FDA in digital health and networked devices.

 

9. Usability / Human Factors Documentation

 

 

  • If the software has user interfaces or is part of a medical device user interaction, documentation of usability testing (formative/summative) and human factors engineering is essential.

  • Provides evidence that the user interface is safe and effective.

 

10. Software Release Notes & Documentation for Submission

 

 

  • For pre-market submissions, the FDA expects summary descriptions of software, including architecture, major revisions, off-the-shelf (OTS) components, site licensing, and training. 

  • The 2023 guidance distinguishes documentation levels: Basic Documentation (for many lower-risk software functions) and Enhanced Documentation (for software where failure could cause serious injury or death). 

 

 

 

 

Documentation Level: Basic vs. Enhanced

The new FDA guidance moves away from the older “Level of Concern” categorisation and instead focuses on Documentation Level: Basic vs. Enhanced. 

 

  • Basic Documentation applies where the software function is unlikely to cause serious injury or death if it fails. Documentation still must demonstrate design control, verification and validation, risk management, but with a lighter burden. 

  • Enhanced Documentation is required when a failure or flaw of the software function could present a hazardous situation with a probable risk of death or serious injury. This requires more detailed process evidence, including development methodologies, independent verification, robust testing, architectural analysis, threat/failure mode analyses. 

Manufacturers should evaluate their software functions and designate the appropriate documentation level in their submission or internal quality system.

 

 

 

Best-Practice Tips for Manufacturers

 

 

  • Start early: Ensure software documentation is generated in parallel with the design & development lifecycle, not retroactively.

  • Adopt standards: Use IEC 62304 for software lifecycle processes, IEC 62366 for usability, and ISO 14971 for risk management.

  • Maintain traceability: A strong trace matrix is essential.

  • Use baselined versions: Control software releases and maintain configuration history.

  • Include third-party/OTS software: Document any “off-the-shelf” components, licensing, versioning, vendor support, and compatibility.

  • Plan for maintenance: Document how updates/patches will be handled, including validation of updates and user notification.

  • Prepare submission-ready summaries: Even if not submitting to FDA (e.g., exempt device), maintain documentation reflecting a submission mindset.

  • Be audit-ready: Design your documentation structure so internal audits, supplier audits and regulatory inspections can be seamless.

  • Leverage consulting support: If navigating complex software or digital health products, engage experienced regulatory/quality consultants (such as Pulse Axis) to ensure documentation is aligned with FDA expectations.

 

 

 

 

Conclusion

Effective software documentation is not simply a regulatory checkbox—it is a strategic asset. For device manufacturers in the United States, aligning software documentation to FDA’s 2023 guidance, adopting robust lifecycle processes, and clearly reasoning your documentation level (Basic vs. Enhanced) are essential steps to achieving regulatory readiness, mitigating risk, and accelerating time-to-market.

At Pulse Axis Medical Device Consulting, we guide our clients through preparing documentation packages, establishing software lifecycle processes, structuring verification/validation evidence, and developing submission-ready strategies. Contact us today to ensure your software documentation is comprehensive, compliant, and future-proofed.