Process verification vs process validation for medical devices

Process verification and validation should be a key part of a medical device manufacturer’s QMS. But what’s the difference between the two? And how does process validation ensure quality for a product’s end user when verification cannot?

Medical device manufacturers need to be certain that their manufacturing processes have the in-built controls necessary to create products that are safe, and meet all of their user, technical and regulatory specifications

Process verification and validation are the way to ensure this happens.

Verification vs validation: what’s the difference:

Typically, verification is said to be about ‘building the thing right’ while validation is about the ‘building the right thing’. In other words, verification is about checking against engineering specifications, while validation is about checking against user needs.

The FDA Quality System Regulation (QSR) frames this in more technical language:

“verification is confirmation by examination and provision of evidence that specified requirements have been fulfilled”

while

“validation is confirmation by examination and provision of objective evidence that the particular requirements for specific intended use can be consistently fulfilled”

Why the distinction?

The ability of some processes to deliver an intended outcome in an end product can be verified through testing. Developers can create KPIs, quantifiable metrics that demonstrate a manufacturing process has worked and an end product is functioning as required. If a process’s KPI is measurable as part of a test, then its success can be verified.

But for some processes, outputs just aren’t quantifiable; they cannot be tested within a reasonable timescale or without destroying the product. For example, the ability to verify an automated build process has been carried out correctly to achieve a consistent result for end users time after time.  

In these cases, there may be no way to check that every single device rolling off a production line has been assembled in precisely the same way according to the specification and will therefore deliver consistent results. Not without taking them all apart, anyway.

Validation supports quality management for complex med tech

Similarly, with the growing technological complexity of modern medical devices and software integrations powered by machine learning, it may be impractical or impossible to retrospectively test for quality, or to devise a test that will demonstrate it will work as expected throughout its entire life cycle.

Instead, the emphasis must be on ensuring the quality of the development process through the meticulous application of standardised procedures by fully trained and accountable workers.

And that’s the purpose of process validation.

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Which processes need to be validated & how?

It’s up to the medical device manufacturer to decide which of their processes need to validated.

But to decide that there are two criteiria to use:

• Is the process output verifiable?
• Is verification sufficient and cost effective?

If neither is the case, then the process should be validated, or the process and/or product should be redesigned in order to allow for verification.

Here’s what the FDA says about it in FDA 21 CFR Part 820.75:

(a) “Where the results of a process cannot be fully verified by subsequent inspection and test, the process shall be validated with a high degree of assurance and approved according to established procedures. The validation activities and results, including the date and signature of the individual(s) approving the validation and where appropriate the major equipment validated, shall be documented.” 

(b) Each manufacturer shall establish and maintain procedures for monitoring and control of process parameters for validated processes to ensure that the specified requirements continue to be met.

ISO 13485:2016 specifies process validation requirements

What should process validation entail?

Advice and guidance is contained in the GHTF guidelines referenced by the FDA.

And ISO 1348:2016 also outlines steps for validation to ensure that processes can produce planned results consistently. These include documenting and implementing the following activities as part of your QMS:

• Systematically identifying and documenting the processes that need to be validated
• Ensuring equipment qualification to show it can produce required results
• Ensuring personnel are trained and qualified to carry out processes consistently and to the required standards
• Utilization of testing methods and criterion for acceptance of processes
• Creation of a sampling plan
• Keeping records of all the activities in the process validation cycle for future auditing
• Documenting when revalidation will be required, for example, after a defined number of units have been produced, if there is a change in process or machinery, or after a certain time interval has elapsed
• If the process is changed, the approving authority for the change has to be defined.

Process validation is an ongoing task

Specifying, documenting and implementing process validation for medical device manufacturing, then, is an ongoing activity.

And given its complexity, it’s one that can only be properly organised through an electronic Quality Management system (eQMS) equipped with the right document management capabilities.

• Having the document control tools available to capture all user requirements and ensure manufacturing processes are developed and specified that deliver on those outcomes is vital for validation and QSR compliance.
• An eQMS can also help you schedule and document required equipment and personnel qualification processes, allowing workers to ‘sign off’ when equipment checks have been undertaken with trackable electronic signatures.
• It can be the repository for the sampling plan to which the whole company can refer.
• It can be the place where all validation records are kept and updated.
• It can trigger reminders for the organisation when revalidation activity needs to take place.
• It can protect documented processes from unauthorised change and document all the authorised changes to processes that take place throughout the device lifecycle.

Conclusion 

Medical Device Manufacturers should start planning their process verification and validation systems as early as possible in their journey to market.  Having the structures in place to ensure you can create and operate processes which deliver consistent user outcomes will be key to the ongoing, commercial success of your product. Being able to demonstrate to the FDA and other regulators that you have those processes in place, and that you can control and audit them effectively, is vital for QSR compliance.