In a highly regulated industry like MedTech, 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. And 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 are not the same thing as design verification and validation. The latter are performed as part of design controls, and have their own specific definitions and steps.
To get some clarity around the difference between process verification and validation, let’s start by looking at the regulations. Since February 2, 2026, FDA’s quality system regulation is the QMSR, In this case, I’m talking about 21 CFR Part 820, which incorporates ISO 13485:2016 by reference. The definitions below originated in FDA’s legacy Quality System Regulation (QSR); the underlying concepts carry through unchanged into ISO 13485 and QMSR.
What is process verification according?
FDA’s legacy QSR (820.3(aa)) defined verification as “confirmation by examination and provision of objective evidence that specified requirements have been fulfilled” — a definition ISO 13485 shares. There is no separate definition of “process verification”; the general verification definition applies 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.
What you need to remember here is that 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 in length, you could verify that by measuring the parts that your process produces against the specification of 20 mm.
What is process validation?
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 does not measure or test a final product against specifications, like when you verify a process is working correctly.
The rule of thumb, consistent across FDA’s legacy QSR (820.75(a)), ISO 13485:2016, and the QMSR: process validation is required 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, you must validate.
In practice, this may include processes like:
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Sterile package sealing
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Aseptic filling
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Welding, soldering, painting, or heat treating
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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:
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Is the process output verifiable? If not, then you should validate or redesign the product and/or process so that you can verify it.
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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:
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Numerical control cutting processes
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Certain human assembly processes
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Certain cleaning process
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Certain filling processes
For complex manufacturing processes and sub-processes, the decision to validate or verify may be more difficult than the examples I’ve used here. Just remember that at the end of the day, 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:
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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.
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Operational Qualification (OQ) - During operational qualification, the equipment should be tested to determine process control limits, potential failure modes, action levels, and worst case scenarios.
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Performance Qualification (PQ) - In 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.
Which comes first — verification or validation?
For processes, neither is a stage of the other. You choose one per process, based on two questions:
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Can the process output be fully verified by subsequent inspection and test? If not — validate (or redesign until it can be verified).
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If it can be verified, is verification sufficient to eliminate unacceptable risk, and is it cost-effective? If yes — verify. If no — validate anyway.
That is the same decision path as the GHTF/IMDRF flowchart above, reduced to its two questions.
The four types of process validation
Prospective validation — validating a process before routine production begins. This is the default and the expectation for new processes.
Concurrent validation — validating during production, justified only when full prospective validation isn’t feasible and controls are in place to protect product released in the interim.
Retrospective validation — relying on accumulated historical production data. Largely disfavored in modern practice; regulators expect validation to be planned, not reconstructed.
Revalidation — repeating some or all qualification activities when a change or signal puts the validated state in question.
When do you need to revalidate?
Common revalidation triggers include: equipment relocation or major repair, new tooling, software or firmware changes, utility changes, calibration failures, repeated deviations or nonconformances, and process data trending out of control. For how requalification is executed stage by stage, see our IQ, OQ, PQ guide.
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