Here is the official FDA regulation for design controls pertaining to design inputs, as found in Part 820.30(c):
Each manufacturer shall establish and maintain procedures to ensure that design requirements relating to a device are appropriate and address the intended use of the device, including the needs of the user and patient. The procedures shall include a mechanism for addressing incomplete, ambiguous, or conflicting requirements. The design input requirements shall be documented and shall be reviewed and approved by a designated individual(s). The approval, including the date and signature of the individual(s) approving the requirements, shall be documented.
ISO 13485:2016 also covers this topic in section 7.3.3 Design and Development Inputs:
Inputs relating to product requirements shall be determined and records maintained. These inputs shall include:
a) functional, performance, and safety requirements, according to the intended use,
b) applicable statutory and regulatory requirements,
c) where applicable, information derived from previous similar designs,
d) other requirements essential for design and development, and
e) output(s) of risk management
These inputs shall be reviewed and approved.
Requirements shall be complete, unambiguous, and not in conflict with each other.
There are several terms used interchangeably when referring to design inputs:
- Design inputs
- Design requirements
- Design input requirements
- Design and development requirements
- Product requirements
Medical device product development should be a holistic process that builds upon itself as the project progresses.
Rushing the product to the market isn’t a recommended best practice in medical device development. Spending time in design inputs will really benefit your project. In device development, establishing design inputs can easily take up to 20% of the entire project timeline.
Writing design inputs takes practice and dedication. Also, design inputs should not just be the responsibility of one person. It’s a team effort. When a team is involved, you get the benefit of everyone’s opinions and experience.
You also should consider all sorts of other sources to help you define design inputs:
- Industry standards
- Previous projects/products
- Competitor products
It’s important to remember that user needs should be established first in order to inform design inputs. Your goals when defining design inputs include:
- Capturing all functional, performance, safety, and regulatory requirements.
- Build upon user needs and intended use.
- Make sure design inputs are clear and objective.
- State design inputs in a way that allows you to prove/disprove them.
You have to consider all types of sources and resources for design inputs. Your design inputs need to be comprehensive, covering all aspects of your medical device.