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Etienne Nichols

CMSC

Process Verification vs. Process Validation

What’s the difference?

Published: Tuesday, February 21, 2023 - 12:03

In a highly regulated industry like medical technology, manufacturing processes must undergo either process verification or process validation to ensure they’re consistently producing the correct result. The question is, which one should you use?

Verification and validation are two different activities, and they’re used under different circumstances. Knowing when to validate or verify a process is essential from both a quality and regulatory perspective.

So, let’s take a look at what process verification and process validation refer to, and when you should use each of them in medical device manufacturing: What’s the difference between process verification vs. process validation?

First, I want to note that process verification and validation aren’t the same thing as design verification and validation. The latter are performed as part of design controls, and they have their own specific definitions and steps.

To clarify the difference between process verification and validation, let’s start by looking at the regulations. In this case, I’m talking about 21 CFR Part 820, otherwise known as the U.S. Food and Drug Administration’s Quality System Regulation (QSR).

What is process verification according to the QSR?

In 820.3(aa) of the QSR, the FDA defines verification as “confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.” There is no specific definition of “process verification” in the QSR, but the general verification definition can be applied to processes as well as products or services.

To verify that a process is working, you need to be able to provide some type of objective evidence—from a test or measurement, for instance—that proves the outcome of the process meets your specified requirements.

Remember, process verification requires some sort of quantitative proof that specifications have been met. In the simplest terms, if you specified that a part should be exactly 20 mm long, you could verify that by measuring the parts that your process produces against the specification of 20 mm.

What is process validation according to the QSR?

The FDA defines process validation as “establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications.”

At first glance, this looks very similar to the definition for verification. However, process validation doesn’t measure or test a final product against specifications, like when you verify a process is working correctly.

In fact, in 820.75(a) of its QSR, the FDA states that process validation must occur “when the results of a process cannot be fully verified by subsequent inspection and test.” In other words, when you can’t use process verification to prove your process is working as intended.

In practice, this may include processes like:
• Sterile package sealing
• Aseptic filling
• Welding, soldering, painting, or heat treating
• Injection molding

In the case of sterile packaging, for example, verifying the result would require opening it—thus destroying the sterile barrier and rendering the whole process moot.

When should you use process verification vs. process validation?

With a process such as sterile packaging, the decision to use process validation instead of process verification is practically made for you.

However, not all decisions regarding process validation vs. process verification are that easy to make. If you’re considering whether you need to verify or validate a process, then start with the IMDRF guidance on process validation. This document includes a flowchart that breaks down the general decision of whether to verify or validate a process.


Source: GHTF Process Validation Guidance

As you can see, the decision revolves around two questions:
• Is the process output verifiable? If not, then you should validate or redesign the product or process so that you can verify it.
• Is verification sufficient and cost effective? Essentially, is verification alone sufficient to eliminate unacceptable risk, and is it a cost-effective solution?

Some processes may be verifiable, but from a business perspective, it may make more sense to validate them instead. The guidance document offers these examples for processes in which you might choose validation over verification:
• Numerical control cutting processes
• Certain human assembly processes
• Certain cleaning processes
• Certain filling processes

For complex manufacturing processes and subprocesses, the decision to validate or verify may be more difficult than the examples I’ve used here. Just remember that you should choose the option that provides the most confidence that this process will result in a safe and effective medical device.

What are the stages of process validation?

If you do choose validation for one of your processes, you’ll then go through the three stages of process validation: IQ, OQ, and PQ, which stand for:

Installation qualification (IQ)

Installation qualification is used to ensure that the installation of any necessary equipment, piping, services, or instrumentation has been executed in accordance with the manufacturer’s requirements.

Operational qualification (OQ)

During operational qualification, equipment should be tested to determine process control limits, potential failure modes, action levels, and worst-case scenarios.

Performance qualification (PQ)

During the performance qualification phase, the goal is to demonstrate that the process will consistently produce acceptable results under normal operating conditions.

If performed correctly, IQ, OQ, and PQ should provide a high degree of assurance that your process will consistently produce the correct result.

First published Feb. 3, 2023, on the Greenlight Guru blog. 

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About The Author

Etienne Nichols’s picture

Etienne Nichols

Etienne Nichols is a medical device guru and mechanical engineer who loves learning and teaching how systems work together. With a Project Management Professional (PMP) certification, Nichols is experienced in manufacturing and product development aiding in the development of combination drug-delivery devices.

Comments

I don't get it.

I am more confused about validation vs. verification than I was before I read this article, and I want to explain why because I think I am the intended audience for this article, but it just did not give me the clarity promised. 

Verification: “confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.”

Validation:  “establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications.”

Distinction: "At first glance, this looks very similar to the definition for verification. However, process validation doesn’t measure or test a final product against specifications, like when you verify a process is working correctly."

Validation is the only definition that includes the word "product," so this immediately threw me for a loop, because given these two nearly-identical definitions, I struggled to find the relevant distinctions, and the only distinction called out here is one that appears to go in the opposite direction when I look at the definitions. There are other distinctions, not examined in the article, which also seem like they might matter: "have been" versus "consistently produces"; and "establishing" versus "confirmation."

Based on the rest of the article, the most relevant distinction I could grab onto was whether a characteristic had to be confirmed via destruction of the part or not. But something in my brain says that just can't be right. Whether I destroy 1000 batches of product to confirm its characteristics, or I test samples of each batch and confirm a state of statistical process control, it seems like either definition could fit either of these activities, but one of them seems more like validation than the other, and it is the use of SPC—not the nondestruction of product—that seems like the relevant distinction in this example because it speaks to the "consistently produces" verbiage of validation's definition. 

I was hoping for a framework for understanding the distinction, but I'm left with my initial impression: similar but different and closely-related activities whose details are the purview of people other than me. 

Clarification

So, is Verification the assessment of the process output relative to its specs? Is validation assessment that the process procedures are being followed, because the output might be difficult or perhaps even impossible to verify? Or am I still missing the point?

THX

Verification - Sample Plans

If a feature can be verified, but you do less than 100% verification using a sampling plan, does the process still require verification? This is a source of debate at our facility. Some features can be verified/measured and the sample is indicative of the process yield. The differing schools of thought are verification in lieu of validation is 100% verification of the feature(s). Validation should be performed for processes as cited in the guidance and this article, but also for any features that are sampled (not 100%). Another thought was that a simple process capability study versus a full-on IQ/OQ/PQ validtion can be used.