Design Validation: More than Just User Testing

Q: Really, in the final analysis, isn’t design validation just user testing?

A: I’ve heard that a lot lately. But it’s not true.

The Quality System Regulation (21 CFR Part 820) includes requirements for design controls. The regulation requires design validation to ensure your design (or design change) meets both defined user needs as well as your defined intended uses.

These needs and uses must be defined in the documentation of your design input requirements.

The regulation also requires that design validation be done under actual or simulated use conditions (my emphasis) with production or production equivalent units. If design validation were only user testing, the regulation would not allow for simulated use conditions.

If design validation were only user testing, the regulation would not allow for simulated use conditions.

FDA clarifies these requirements in its Design Control Guidance for Medical Device Manufacturers:

“The requirements which form the design input establish a basis for performing subsequent design tasks and validating the design.”

Furthermore, under the Validation Methods section of the Design Control Guidance, FDA says:

“Many medical devices do not require clinical trials. However, all devices require clinical evaluation and should be tested in the actual or simulated use environment as a part of validation. This testing should involve devices which are manufactured using the same methods and procedures expected to be used for ongoing production.

“While testing is always a part of validation, additional validation methods are often used in conjunction with testing, including analysis and inspection methods, compilation of relevant scientific literature, provision of historical evidence that similar designs and/or materials are clinically safe, and full clinical investigations or clinical trials.”

So design validation is really what happens near the end of the design or redesign of a medical device. It’s done as a set of various activities to answer the question, “Does this design solution actually perform and function as I intend it to, and does it meet my user needs?”

Design verification activities provide theoretical assurance that the design is appropriate in regard to your defined design input requirements.

However, design validation provides evidence — beyond theoretical assurance — that the device you designed is truly safe and effective within the context of those same design input requirements.

Answered by Denise Dion, Vice President of Regulatory and Quality Services for EduQuest, who served 18 years at the U.S. FDA as an expert field investigator and who was a member of FDA’s Design Control Inspection Strategy team. Denise is the lead instructor for EduQuest’s two-day training class, Design Control for Medical Devices: Meeting FDA’s 21 CFR Part 820.30 Rules for Quality Design and Manufacturing.


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