Final answer:
Translation of device design into production specifications is not a requirement under the device design validation section of the QSR. Design validation focuses on ensuring conformance to user needs, testing under real or simulated conditions, and software validation if applicable.
Step-by-step explanation:
When design validation activities are being conducted by a manufacturer, the element that is NOT included as a requirement under the device design validation section of the Quality System Regulation (QSR) is D. Translation of device design into production specifications. Design validation ensures that devices conform to defined user needs and intended uses, which includes A. Conformance to defined user needs and intended uses, and involves B. Testing of production units under actual or simulated use conditions. Validation activities must also include C. Software validation if the device includes software components.
The objective of design validation is to ensure that the final product will perform reliably in the real-world scenario for which it was intended. This typically involves thorough testing and evaluation of the device. Prototypes were not tested adequately indicates that there may be weaknesses or deficiencies in the design. The validation process might reveal the need to refine the design to meet the necessary quality and performance criteria better. Evaluation of a design's quality can focus on attributes of the product and how well it meets user needs and intended purposes.
To improve the product design based on findings from validation activities, engineers might need to go back to earlier development phases, such as the 'Select a design concept' step, demonstrating the iterative nature of design validation. The key is to ensure that the design not only meets theoretical specifications but also performs well in the real-world application, which is the essence of validation, distinguishing it from the translation of design into production specifications, which is rather a part of the design transfer phase.