ISO 13485 from zero, episode four: design controls in the order they happen.

Who is this episode for?

This is episode four of ISO 13485 from zero. It is for companies that design their own devices. If you only make to someone else's design or distribute, you may have excluded design from your scope, and you can skip ahead. For everyone else, design controls are where the device's safety and performance are decided, and where the design history file is built.

What goes in the design plan?

Each design project needs a plan that sets out the stages, the reviews at each stage, the verification, validation and transfer activities, responsibilities, and how the design will be traced from inputs to outputs. The plan is a living document. Update it as the project changes, and keep the versions.

What makes good design inputs?

Functional and performance requirements from the intended use, safety requirements including the outputs of risk management, usability requirements, and applicable regulatory requirements and standards. Inputs must be complete, unambiguous, able to be verified or validated, and not in conflict with each other, and they must be reviewed and approved. Most later problems trace back to inputs that were vague. Write each input so that someone could design a test for it.

What are design outputs?

The results of design work: drawings, specifications, software, labelling, manufacturing instructions. Outputs must meet the inputs, provide information for purchasing, production and servicing, and include or reference the acceptance criteria. Approve them before release.

Template for this step: the design review, V&V matrix and DHF templates are in the ISO 13485 Design Controls & DHF Kit ($149).

How should design reviews work?

At the stages set in the plan, review the design against requirements. Include representatives of the functions concerned, and at least one person who is not directly responsible for the stage being reviewed. Record who attended, what was reviewed, the decisions and the actions.

What is the difference between verification and validation?

Verification confirms the outputs meet the inputs, usually through tests, inspections and analysis. Validation confirms the device meets the user needs and intended use, under defined conditions, on production-equivalent units, and may include clinical evaluation and usability evaluation. Plan both, record the methods, the acceptance criteria and the results, and make sure the units tested are traceable.

What about transfer and design changes?

Design transfer moves the design into production, confirming the outputs are suitable for manufacturing. After that, every design change is identified, reviewed, verified or validated as appropriate, and approved before implementation, with its effect on risk, on product already made and on regulatory status assessed. All of these records together form the design history file.

The ISO 13485 Design Controls and DHF Kit contains the plan, input and output records, review records, and verification, validation and transfer templates. Previously: risk management. Next episode: purchasing and suppliers.