Breaking Down the Verification and Validation Processes for Medical Devices
Developing a medical device starts with identifying every user need your final product will meet. Then, those needs are translated into actionable product specifications. These are called design inputs.
Why do design inputs matter? Because if you don’t satisfy your design inputs, your product won’t satisfy user needs. And if you don’t satisfy user needs, no one will want to use your product if and when it makes it to market.
But simply incorporating design inputs into your medical device design isn’t enough. You are required to follow proper design controls and provide evidence that you really did meet these specifications and your product really does work for the intended users.
Charting this evidence is all a part of verification and validation. And even though all medical device developers go through verification and validation, these processes can be overwhelming and difficult to understand.
To help, we break down both verification and validation below. Additionally, we detail a tool that can help you track it all.
Understanding the Medical Device Verification Process
After you translate user needs into actionable design inputs, all product stakeholders must sign off on the design inputs. This could include:
Once all applicable parties are on board with your design inputs, the actual design work begins. As you’re designing your medical device, you’re organically creating design outputs.
The FDA defines design outputs as:
The results of a design effort at each design phase and at the end of the total design effort. The finished design output is the basis for the device master record. The total finished design output consists of the device, its packaging and labeling, and the device master record.
Put more simply, design outputs are the manifestation of your design inputs in your medical device design.
Verification is the process of ensuring your medical device satisfies the design inputs. It requires you to document each of these design outputs because they are evidence you met the design inputs.
Note that verification takes place throughout the entire product development cycle through to the last, signed-off final design review, right before production begins.
Possible Verification Results During Product Development
There are a number of tests that can be conducted during the verification process to confirm your outputs against your desired inputs, including:
Thermal analysis of an assembly to assure that internal or surface temperatures do not exceed specified limits
Fault tree analysis of a process or design
Failure modes and effects analysis,
Package integrity tests
Biocompatibility testing of materials
Bioburden testing of products to be sterilized
Comparison of a design to a previous product that has an established history of successful use
It’s important to understand that although qualification testing can happen before verification and throughout the design process. Qualification testing can provide confidence in the direction of your medical device design.
Some qualification tests do provide recordable verification results. But in general, it’s best to view qualification testing as practice for the required verification and validation processes.
Once verification testing is completed, your CAD files are released and actual production — including tooling builds and production of parts — commences.
Understanding the Medical Device Validation Process
The validation process starts as soon as you have the production equivalent parts and assemblies, or first-off tooling parts.
While verification ensures you’ve made your medical device correctly, validation confirms the finished product meets its intended use in its intended environment.
Possible Validation Tests
The validation process often includes summative usability testing. Just as it sounds, summative usability testing summarizes the accomplishments of the design process by testing a production-like system at its conclusion. On the whole, it validates how usable and safe your product is through defined measurements, reducing the risk of costly surprises.
Say your product is meant to be used in extremely cold environments. A summative usability test would ask a user to manipulate and use your product in the frigid environment. You’d validate details like whether the user can hold the device in his hand with his mittens on, if hinges stick in the extreme weather, and so on.
If pivotal clinical trials are required, they also happen during the validation phase of medical device development. Pivotal clinical trials are crucial because their results will be evaluated by regulatory authorities (like the FDA) to determine whether or not your medical device is safe and effective enough to move forward to commercialization.
No matter what kind of testing you conduct during validation, know that it will likely include a lot of hands-on trials with actual users.
If all goes well with your validation process, you’ll sign-off on the testing report(s) and move forward with your development plan. On the other hand, if validation doesn’t go well, you’ll need to revisit and potentially alter your design inputs. For instance, you could specify in your instructions that your product doesn’t actually work well if the user is wearing mittens.
The Critical Role of a Traceability Matrix in Verification and Validation
A traceability matrix is a spreadsheet or visual map showing your entire list of requirements (transposed into design inputs) and how, during verification and validation, they’re fulfilled.
Although most medical device companies wait too long to start the verification process, you should ideally fill in your traceability matrix as your design produces outputs that verify your inputs.
By starting as soon as you can, you give yourself time to address any issues that pop up before you’re too far into development to make design or product changes. The traceability matrix helps you track everything in one easy-to-access place.
Your verification and validation processes will only go smoothly if you’ve thoroughly documented user needs and their subsequent design inputs before you start designing or considering verification and validation.