Design History File – Explained

In the highly regulated world of medical device software development, compliance with US regulatory requirements such as the FDA’s 21 CFR Part 820.30 is non-negotiable. A fundamental aspect of this compliance is the creation and maintenance of a Design History File. Initiated at the start of a project and sustained throughout the entire lifecycle of a medical device, the DHF serves as a thorough and living record of the design and development process, capturing critical information about the software and its associated documentation.

The Design History File is a comprehensive and well-organized collection of documents that provide a detailed narrative of how the software was designed, developed, tested, and brought to market. Within this file, one can find design plans, design inputs and outputs, design verification, and validation testing documents, as well as risk analysis and mitigation reports. The DHF is a living document; it evolves as the product progresses, capturing any design changes made during the development process and the rationale for those changes. Moreover, it is designed to be exhaustive, aiming to leave no questions unanswered about how and why each design decision was made. In the event of regulatory audits or inspections, the Design History File acts as the central repository of information that shows the product was developed according to required standards. Ultimately, the DHF is not just a regulatory requirement—it is a best practice that reinforces methodical, disciplined development, promoting the creation of safe and effective medical device software.

The DHF serves several purposes within the medical device software development process:

• Regulatory Compliance: The DHF is a regulatory requirement enforced by authorities such as the Food and Drug Administration (FDA) in the United States and other regulatory bodies worldwide. It demonstrates that the software has undergone appropriate design controls and meets the necessary safety and efficacy standards.
• Traceability: The DHF enables traceability by capturing and linking all design and development activities, ensuring that each step is accounted for. This facilitates identification and resolution of issues and allows for efficient audits and inspections.
• Documentation of Design Controls: The Design History File contains documentation related to design controls, including design plans, design inputs, design outputs, design verification, and validation activities. These records demonstrate that the software has been developed according to predefined requirements and specifications.

Each component of the DHF is designed to systematically capture key aspects of the design and development process, forming a thorough and cohesive record that stands as a testament to the safety, efficacy, and quality of the medical device software.

The information included in a Design History File (DHF) differs by device, so it is hard to give a specific example of a Design History File. The graphic below shows some of the common elements included in such documentation that influence the final version.

The Design History File (DHF) should document every part of the software design process. Different phases are represented in dedicated DHF sections:

• Design and Development Planning: This section of the Design History File (DHF) provides a high-level overview of the medical device software development process, setting the stage for the entire project. It includes a detailed project plan that outlines key milestones, tasks, resources, schedules, and responsibilities, acting as a roadmap that guides the development team through the intricate process of creating medical device software. Critical to this stage is the risk management plan, which illustrates strategies for identifying, assessing, and addressing potential risks associated with the device, establishing a proactive approach to safety and effectiveness. This foundational section ensures that the project is organized and structured from the outset, contributing to a more efficient and focused development process, helping to mitigate unexpected challenges that may arise as development progresses.
• Design Inputs: Design Inputs are the fundamental building blocks of a medical device software project, representing the specific characteristics of the particular device. These inputs are detailed requirements based on user needs that the software must meet, acting as the criteria against which the final product will be judged. They can include user requirements, regulatory requirements, safety standards, and other relevant specifications that guide the software’s development, ensuring that the device will be safe, effective, and compliant with all necessary regulations. Establishing thorough and precise design inputs is a critical early step in creating medical device software, setting the stage for successful design outputs, verification, and validation activities.
• Design Outputs: Design Outputs are detailed specifications, drawings, and documents that describe the device and its components in a manner sufficient for it to be produced. These outputs are the tangible results of the development process, encompassing software architecture diagrams, algorithms, source code, graphical user interfaces, and other essential components that are generated based on the design inputs. They serve as the basis for design verification and validation, offering concrete, measurable items that can be compared directly to the initial design inputs to ensure that all specified requirements have been met. Maintaining detailed and organized design outputs is essential for regulatory compliance, as these documents illustrate the meticulous nature of the device’s development process and are a critical element of the Design History File (DHF).
• Design Verification and Validation: The Design Verification and Validation section of the Design History File (DHF) uses systematic, objective methods to demonstrate that the design outputs are consistent with the design inputs and that the final product meets user needs and intended uses. These activities may involve reviews, inspections, and testing, each of which is comprehensively documented to provide a clear and traceable record. On the other hand, validation activities involve rigorous testing under actual or simulated conditions to confirm that the final product effectively conforms to user needs and intended uses, showcasing that the software will perform safely and effectively in the hands of the end user. If discrepancies are identified during these tests, corrective actions are taken and meticulously documented in this section, ensuring that every step is taken to refine the software into a product that meets all specified requirements, and is safe and effective for its intended purpose.
• Risk Management: Risk management is a crucial component of the Design History File, serving as the foundation for proactive identification and handling of potential issues throughout the medical device software development process. It begins with a comprehensive identification of potential risks associated with the software, considering various scenarios in which the software might not perform as intended, or might interact negatively with other systems or devices. Following this, a thorough assessment is conducted to evaluate the likelihood and severity of these identified risks, prioritizing them based on their potential impact on patient safety and device effectiveness. Based on this assessment, specific risk control measures are then developed and implemented to mitigate or eliminate these risks, ensuring that the software meets the highest standards of safety. In this section of the DHF, documentation such as risk analysis reports, risk assessment tables, and risk control plans are meticulously compiled, providing clear evidence of systematic, data-driven decision-making aimed at ensuring the safety and effectiveness of the medical device software.
• Design Changes: This section meticulously documents any alterations made to the software design during or after the development process, serving as a comprehensive record of the evolution of the design. It includes change control procedures, which clearly outline the systematic approach of how design changes are proposed, reviewed, approved, and implemented, ensuring that every modification is deliberate and properly authorized. Records in this section detail the precise impact of these design changes on the overall system, illustrating how they affect the software’s functionality, safety, and performance. Additionally, this section elaborates on how these changes were managed and controlled, showcasing the company’s commitment to maintaining the integrity and quality of the medical device software throughout its lifecycle, even as adaptations are made.
• Design Transfer: This critical stage involves moving the finalized design from the research and development stage to production. This phase ensures that the design, along with all associated documentation and specifications, is effectively communicated and transferred to the production team to ensure consistency and quality in the final product. It includes documents that verify that the manufacturer can consistently produce the device according to the design outputs and under a controlled production process.

Below, you’ll find the phases of design control to help you visualize it.

The Design History File serves as a comprehensive and structured record of the entire design and development process of a medical device. Each of these integral components—initial planning and input definition, verification and validation processes, and the final transfer of the design into production—are essential to ensure the safety, effectiveness, and quality of the final medical device software. With these components well-defined and documented, the DHF becomes a key tool not only for regulatory compliance but also for maintaining high standards of quality and accountability.

In the next article, we will delve deeper into how you can create a DHF in an Agile way. We will provide a step-by-step guide on how Agile methodologies can be effectively implemented when developing Software as a Medical Device (SaMD) according to IEC 62304 & ISO 14971 standards. There is a lot of great content coming! To ensure you never miss a future article in the series, sign up for our SaMD newsletter today and get latest articles directly to your inbox.

Creating and maintaining a comprehensive Design History File (DHF) is essential for regulatory compliance and successful medical device software development. The DHF serves as a record of the design and development process, capturing critical information related to design controls, verification, validation, and risk management.

Software developers, manufacturers and stakeholders in the medical device industry should always ensure that their DHF is well-structured, complete, and up-to-date. A robust DHF not only enables compliance with regulatory requirements but also enhances traceability, facilitates issue resolution, and ultimately contributes to the development of safe and effective medical device software.

Creating a Design History File (DHF) might be challenging and time-consuming, but there are ways to optimize this process. At HTD, we create DHF in an Agile way and we use the electronic Quality Management System (QMS)  from Greenlight Guru. This allows us to significantly accelerate the software as a medical device (SaMD) development process and creation of DHF while staying agile and ensuring compliance with all the regulatory requirements.

If you are looking for expert assistance in creating your Design History File or require further guidance on software development in the medical device field, schedule a free consultation with an HTD Health SaMD expert. Reach out to info@htdhealth.com and we will be more than happy to help you! The HTD team is here to support you throughout the entire process while ensuring regulatory compliance and highest quality of end products.