How Are Medical Device Requirements Used in Design Control?
Lets consider a software controlled electromechanical medical device system.
User Requirements are created first. They are developed by Marketing and Management. They consider the medical device system as a “black box” and list only what the user should experience in his use of the medical device. An example is “System shall analyze 30 samples per hour”. User Requirements are the basis for later system validation.
From the User Requirements, Functional Requirements are developed. They are high level technical requirements for what the medical device will do, not how they will be done. They are developed by Marketing, Management, and Technical Management. They are the basis for verification.
Technical Management then decides if each Functional Requirement will be implemented in the medical device design by system hardware or software.
The Software Requirements are generated from this list by Technical Management and software developers.
The Software Requirements are translated into architecture by software developers (the software design). These are modules of software functionality.
The software coder writes code for each architecture module.
The medical device system hardware (motors, sensors, pumps) are designed per the hardware Functional Requirements. The Engineering department decides how to meet the Functional Requirements as part of the design process. The design process is reviewed and documented per Design Control SOP's.
System hardware is tested (verified) against the hardware Functional Requirements.
Software is verified/validated against the Software Requirements (code reviews, unit tests, etc)
The system/ product is then validated against the User Requirements.
SOP’s to control each of these steps are available from MedDevice Advisors.