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Simple Understanding of Medical Device Design and Process Verification/Validation


What Do I Need to Know About Medical Device Verification and Validation

Question: What are the differences between medical device verification and validation (V&V) and process V&V?

Answer: Verification and validation are about gathering evidence to prove a specific hypothesis. Design and process V&V work together. However, they differ based on what you are trying to prove.

Product development and process development should be included and integrated throughout the medical device product development project. Each contributes important information necessary for the device’s success.

Medical Device Design Verification and Validation

Design V&V demonstrates your product was designed correctly.

Design verification shows that your product meets the design inputs or that you designed what you planned to design. In this case, you are measuring your design against quantitative product requirements; for example, 99% accuracy or weighs less than 8 pounds. Design validation, on the other hand, demonstrates the product meets the customers’ needs, which are often qualitative. Examples include highly accurate or lightweight. In addition, design V&V demonstrates your product is safe and efficacious for its intended use.

When running design verification, you may use components of the final device to demonstrate you’ve met a particular requirement. This method works well when using a V model for development. However, you will need to maintain a test product pedigree (complete identification of parts and assembly) and demonstrate how the tested assembly compares to the final product. If the components change between testing and launch, keep track of all the changes and evaluate the need for regression testing.

Design validation should be tested with a production-like product. Some companies use samples from the process V&V runs for their design validation. If waiting for production results in a significant delay, consider using earlier samples. You will need the product design under full revision control. Document the product pedigree. Any changes between this form and the final production product will need justification for acceptability and potential regression testing.

Design V&V must use protocols, but does not need to exercise the production documents. The outputs from design V&V may be production documents and tolerances, but also includes reports such as stability, shipping studies, safety, biocompatibility, clinicals, country specific labeling, etc.

Medical Device Process Verification and Validation

Process V&V demonstrates your device can be manufactured to specifications reliably and repeatedly.

The specifications will come from the design group, plus any operational specifications to ensure reliability. The device consists of the actual device, plus packaging and labeling. In addition to your reports, the output is expected to show that you can follow the manufacturing documentation (drawings, procedures, tolerances, test processes, etc.)

The difference between verification and validation is that you must validate when the process cannot be inspected or checked for correct assembly/treatment. For example, sterilization.  You cannot see whether the product is sterile, so you validate that process. You may also choose to ensure the manufacturing process has a high degree of process capability (Cp, Cpk) to minimize the amount of testing required.

Often process V&V uses IQ/OQ/PQ to demonstrate the process delivers the final product. IQ or installation qualification is used when installing the equipment (production or test). This process ensures you have space for new equipment, the correct infrastructure, and the equipment operates through the expected setting ranges. When you are using the same equipment for a new product, the IQ may be skipped if the new product uses ranges already established on the equipment.

The OQ is the operational qualification. In this step of the V&V process, you demonstrate acceptable product can be manufactured within a range of equipment settings. Companies often use Design of Experiments (DOE) to find the critical parameters and optimize the process. Once the parameters are defined, several runs of the product are manufactured using best and worst case parameters to ensure the product is acceptable. Since no piece of equipment runs at optimal settings all the time, this testing provides the ranges for acceptable equipment tolerances.

The product qualification (PQ) establishes the product can be made in production like runs. The PQ parameters use nominal settings and should represent typical production run duration and quantities.

Any of these qualifications may be combined. Some of these may be tested at the equipment manufacturer (through Factory Acceptance Testing or FAT) before being transferred to the final production location. The qualification testing typically measures more parameters than will be used in the final production setting. For example, a molded product may test many dimensions while setting up the mold and molding parameters. However, the final product may only use pressure, time, and a single critical to quality (CTQ) measurement to ensure the run is in control.

The output of process V&V will include reports, final production documents, and completed design transfer.

Common Elements

Both design and process V&V require protocols with pre-determined acceptance criteria and statistically valid sample sizes.

Collaboration between design and process V&V can help minimize the number of runs, samples, and testing needed to properly validate the product. In addition to process variability, you should build in timing and material lot variability. All testing must be completed using validated test methods.

Closing Thoughts

Design and process V&V are different, but each contributes important elements to help ensure your product’s success. A great product design that meets all the customer requirements, but can’t be manufactured at an acceptable quality and price is just as bad a high quality product that doesn’t meet the users’ needs.

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