After all of these years “under the umbrella” of The Quality System Regulation and ISO 13485, there is still much confusion in the medical device industry differentiating between validation and verification (even in its most unassuming format). Personally, I had to work hands-on with these process tools until the puzzle pieces finally came together. There are many variables and twice as many approaches. From my observations, academicians who vicariously discuss these subjects are commonly confused and spread their misperceptions without regret.
Quite simply, and in a very general sense, verification and validation is a corroborated process of ensuring that a product design meets deliberately planned requirements. Requirements can come from customers, the Federal government, sales and marketing departments, design engineers, competent authorities, quality engineers, manufacturing associates, etc. Let’s break this enigma down to practical simplicity so that we have an overarching understanding of the two terms before moving forward. I realize that there are a lot of definitions and examples to initialize this conversation, but having a basic and calibrated understanding of the QS Regulation and the harmonized 13485 Standard is an important first step for all of us to embrace.
1. Verification confirms that the device properly reflects the requirements specified, ensuring that you built it right.
2. Validation confirms that the device will fulfill its intended use, ensuring that you built the right thing.
Note: It is entirely possible that a device passes prescribed testing when verified, but fails when validated. This can happen when a product is built as per the specifications, but the specifications themselves fail to address the functional needs of the product or process. Validation and verification walk down the road together and even hold hands on occasion, but they are very different in so many ways.
Definitions from 21 CFR, Part 820 (as harmonized with ISO 8402):
Note: FDA adopted the ISO 8402 definitions for validation and verification. These two basic definitions are also consistent with the definitions in ISO 9000.
- Verification means confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.
- Validation means confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use can be consistently fulfilled.
...and now, more specifically:
Process Validation means establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications. Process validation ensures that the process consistently produces conforming results and products when it is controlled appropriately. Validation of the process results in establishing and confirming adequate process control methods on the basis of scientifically valid rationale.
Discussion – Production units must be included in the design validation and tested under conditions similar to those that are expected to be experienced in the user environment. Design validation may require coordination with process validation activities, i.e. produce devices for Design validation activities using a validated process foundation and qualified machinery.
Examples of traditional processes that have been considered by FDA to require validation are test methods, welding, injection molding, sanitization, mixing, sterilization, aseptic processing, software-controlled processes, water systems, extrusion, cleaning, lyophilization and sealing.
Design Validation means establishing by objective evidence that device specifications conform to user needs and intended use(s). Design validation ensures that the finished device meets the users’ needs and the requirements for its intended use. Design validation follows successful design verification.
Discussion – Design verification is not a substitute for Design validation. Design validation should be performed under defined operating conditions and on multiple initial production lots or batches. Design validation may also be carried out in earlier stages before initial production. It may be necessary to perform multiple validations if there are different intended uses. Design validation requirements include product software validation and completion of risk analysis.
Examples that have been considered by FDA as Design validation activities are clinical studies, use tests, simulated use tests and clinical search/experience reports.
Design Verification shall confirm that the design output meets the design input requirements.
Discussion – Design verification consists of specific activities performed during the design process that ensure that the defined process is being followed correctly and that the design inputs are met. Typical verification activities are documented inspections, tests, analyses and objective evaluations.
Examples that have been considered by FDA as design verification activities are animal model tests, biocompatibility tests, material and device compatibility tests, functional tests, reliability testing and performance tests. For software, typical verification activities include code reviews, schematic reviews, unit and component tests and integration tests.