Software verification and validation is a process that produces objective evidence that the software in a medical device has been thoroughly designed, tested, and meets user requirements. The level of depth of testing and documentation is based on overall risk. This installment of ‘Ask the Engineer’ addresses the question of when and where to start the software verification and validation process.
Q: What does software validation consist of?
Myth: Software Validation consists of DV (Design Verification) phase tests which provide evidence that the software user requirements have been fulfilled.
Fact: Software Validation starts at the first phase of any project containing software. Per the FDA, Software Validation is ‘confirmation by examination and provision of objective evidence that software specifications confirm to user needs and intended uses, and the particular requirements implemented through software can be consistently fulfilled’ (footnote – GPSV). As we all should know, this objective evidence is the documentation and tasks that need to be authored, reviewed, and executed, including but not limited to:
- SDP (Software Development Plan)
- SCMP (Software Configuration Management Plan)
- SRS (Software Requirements Specification)
- LOC (Level of Concern)
- SRA (Software Risk Analysis)
- SDD (Software Designed Documents both high level architecture and low level module design)
- SVP (Software Validation Plan and report of plan execution) consisting of:
- Unit Test Plans
- Integration Test Plan
- Software System Test Plan
- User needs to Intended Use Test Plan
Embracing these activities in the process while they are relevant greatly reduces effort. The longer the validation process is pushed out, the more the task/process morphs into a new separate, possibly expensive project. The Software Validation process and its associated tasks do not take place in the DV phase alone nor should it start there.
Q: What does software verification consist of?
Myth: Software Verification consists of successfully executing, in the DV (Design Verification) phase, Unit level, Integration level, and Software System Tests.
Fact: Each phase of the product development process has a Software Verification component. Software Verification per the FDA is ‘confirmation by examination and provision of objective evidence that specified requirements have been fulfilled’ and ‘output of a phase of development meets all the input requirements for that phase’ (footnote – GPSV). Each phase of development has inputs and outputs. In the software world, verification consists of reviewing generated documents, code walkthroughs, static and dynamic analysis, as well as the actual testing.
In the simplest example of early embracement of software verification, we can design Unit and Integration test during our Design and Implementation phases. Coupling these test designs with an SVP and Unit, Integration test plans, allows the ‘System’ to continually verify the development and engineering cycle. This technique practically eliminates surprises and also provides a high level of confidence that the final DV exercise will be an easy to schedule, formal effort, rather than a series of unknowns. Software Verification is a required process and if we embrace it early in the product development process, we can eliminate many sources of risk as well as ensure compliance to the standards.
Q: Can you add / buy Software Verification and Validation as the last step of Medical Device Product Development?
Fact: It’s possible and it has been done this way, but after truly understanding the Software Verification and Validation process, trying to implement and complete the associated tasks at the end of the development process minimizes the inherent confidence you will have in the software. Handling the V&V process at the end of the project will also make your documentation package read like an add-on, thereby increasing FDA scrutinization. Software V&V is a process that should start at program onset. Each phase of the project development lifecycle contains elements which require Software Verification and Validation, and conducting these tasks in the appropriate phase reduces risk to the patient, user and company. By accepting Software Verification and Validation as a continuously woven thread through all phases of project development, then and only then will you gain full confidence in the overall system in addition to complete regulatory compliance.