When your medical device product development project gets to Design Verification and Design Validation, do you feel like it's almost there?
Meaning, finally, you can see the goal of market release coming soon?
Or is it more like being stuck in the middle?
From my product development experiences, entering into Design Verification and Design Validation is always bittersweet.
Exciting because yes, to get to Design Verification means that we have accomplished quite a bit.
Terrifying because the work ahead can be frustrating, time consuming, and sometimes ambiguous.
Let me share a few perspectives from a recent project.
Then I'll get into explaining exactly what Design Verification and Design Validation are, how they are the same, and how they are different.
The device is an electronic medical device with firmware. Early design and development activities were trying. The team changed, the design changed. Lots of back and forth, with seemingly little to no progress at times.
But then we found ourselves at the edge of Design Verification and preparing an FDA 510(k) submission.
As project manager, I realize getting to this point in the project is a significant milestone. But I'm not a complacent person. The goal is market launch.
And when you are about to enter into Design Verification and Design Validation, you quickly realize how important the earlier Design Controls activities are to your project.
Did you capture the right User Needs?
Are your Design Inputs written well-enough?
Do you have sufficient Design Outputs?
What happened during Design Reviews?
So here we were, about to begin Design Verification. We had a loosely defined plan for all the Design Verification activities. And then we just dove right in.
While we were addressing Design Verification, the startup CEO only heard that we were preparing the 510(k), which in his mind was more meaningful and significant.
Should I have explained the importance of Design Verification and Design Validation to the CEO? Or was he right to focus on the 510(k) submission?
Maybe it's a matter of semantics. Not sure it matters either way.
Regardless, let's now get into the specifics of Design Verification and Design Validation that the startup CEO didn't want to.
Let me dive into explaining what they are, how they are the same, and how they are different.
Design Verification & Design Validation - What?
All too often in medical device product development, the terms "verification" and "validation" are thrown around. Many times they are lumped together as "V&V" as kind of one thing or phase. I'm not here to debate whether this thinking is right or wrong.
There are times when I see Design Verification as something very different from Design Validation. And plenty of other times when I refer to V&V.
First, let's clear up a bit of terminology about "verification" and "validation". These "V" words without descriptive adjectives are too vague.
For instance, if someone asks you about verification, you need them to clarify what they mean. There are multiple types of verification and validation: Design, Process, and Software are the most common in the medical device industry.
And each means something different. Also, to complicate matters a bit, outside the medical device industry, verification and validation also mean different things.
The focus of this post and the relevant terms for Design Controls are Design Verification and Design Validation.
I'm only focusing on these versions for the time being. (So from this point forward in this post, if you read "verification" I'm referring to Design Verification and "validation" refers to Design Validation.)
Even with this Design Verification and Design Validation can be confusing. To help clarify, remember these two simple questions:
- Design Verification: Did you design the device right?
- Design Validation: Did you design the right device?
Be sure to note the subtle, but extremely important, difference.
Design Verification Is More Than Testing
I suspect when most medical device engineers hear the term "Design Verification" they think of one thing: testing.
While it is true and very likely that Design Verification will involve testing, there are other acceptable verification activities. Design Verification activities can include tests, inspections, and analyses (for a full list, refer to FDA Design Control Guidance section "Types of Verification Activities" on page 30).
The natural tendency and trap is to fallback and rely too heavily on testing for Design Verification.
Don't fall into this.
Remember, the purpose of Design Verification is to confirm your Design Outputs meet your Design Inputs. This is why you have to think about Design Verification when defining Design Inputs.
Design Verification testing has pitfalls. There are plenty of cases where inspection and analysis activities are just not sufficient for verification and testing is the only way.
Keep in mind, though, that testing is often very expensive, time consuming, and subjective.
Expensive because you usually have to have lots of test articles. Expensive because you may need to involve third party testing resources.
Time consuming because testing multiple test articles, especially if third party testing firms are involved.
Subjective because you may try to do the testing yourself to save money and time. But if you don't test to an accepted method or protocol, your tests are not objective.
Again, there are plenty of times where testing is the only way to verify. My advice is to also consider other verification activities.
Importance of a Design Verification Plan
For the reasons described above, a Design Verification Plan is important. And the time to construct a verification plan is when you define Design Inputs.
If you wait to construct a Design Verification plan right before starting verification, this is too late.
This is why I stress over and over the importance of considering how you will verify Design Inputs when you are defining Design Inputs.
Consider that instead of rushing to Design Verification, the opposite approach might be more beneficial. Spend more time defining Design Inputs so that Design Verification becomes smoother.
Implementing this approach will help you to become a better Design Input artist and your ability to better manage medical device product development
Design Validation Proves The Right Device Was Designed
The purpose of Design Validation shall prove the medical device meets the User Needs and intended uses.
And Design Validation is a Design Controls activity that happens pretty late in the product development process.
But yet validation is a measure of one of the first activities--defining User Needs.
Design Validation Musts
Design Validation must include initial production units.
This means the medical devices used for validation have to be built in the production environment, using drawings, specifications, etc. (i.e. Design Outputs) by production personnel.
Design Validation must involve clinical evaluation.
This means that the end-user(s) should be involved and the device should be tested either under simulated use or actual use.
The medical device should be used under the specific environmental conditions.
"Clinical evaluation" does not just mean actual use. (NOTE: Actual use requires quite a bit of additional criteria for most devices. You can't just go and have your medical device used in actual use without addressing this first.)
Design Validation must involve testing.
Tests are required to demonstrate your medical device functions as expected and meets the User Needs. You can also incorporate inspections and analyses as part of validation in addition to testing.
Design Validation must include packaging and labeling.
Your medical device includes everything from the label, the instructions for use, the packaging, and everything inside your packaging. Validation must include all of it.
Yes, Design Validation Planning Is Important
Like Design Verification, it is important to plan Design Validation and to do so earlier in the project. I advise planning validation at about the same time as Design Verification planning.
There is a definite relationship between verification and validation. If planned properly, there are ways you can accomplish Design Verification and Design Validation with the same activities.
Thinking about how you will validate a particular User Need can happen when these are defined.
Design Validation, though, can be a bit tricky, especially in determining if you have effectively demonstrated your medical device meets User Needs.
There is usually more of a human element to validation and subjectivity can be an issue. Plus, the ways you choose to solicit end-user feedback is important.
Are you going to be present and observe the end-user? Are you going to send the medical device, complete with packaging, labeling, and IFU, to the end-user and require a survey be completed? How will you know you successfully completed Design Validation?
These are all considerations of validation planning.
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