Page 66 - Biomedical Engineering and Design Handbook Volume 2, Applications

FDA MEDICAL DEVICE REQUIREMENTS 45

(4) Design validation
(5) Design transfer
A major difference in philosophy from previous GMP systems is that these five stages are not
one-time events. Each time a change in design occurs, it must be analyzed to determine whether cer-
tain of these steps must be repeated. Different types of changes may require different loops through
the system. It must be determined, for example, if verification or validation must be repeated on the
parts of testing that are affected by a change. This makes the design control process a living system
that is always being probed, rather than a single historical process.
(1) Design input
This phase covers the gathering and specifying of all the requirements for the product:

Each manufacturer shall establish and maintain procedures to ensure that the design requirements relat-
ing 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 con-
flicting requirements.
Id. § 820.30(c).
Note that the needs of the user and patient are to be considered. This does not make a customer-
focused system a matter of law, but it does create a requirement to do analysis of the needs of
all the audiences. Device companies use various procedures to amass and document the inputs.
Some companies start with a general functional list of features, which is sometimes called mar-
keting requirements. This may be followed by a more detailed list of the engineering require-
ments needed to implement them. Some companies merge these two into one process. In any
case, the needs of all users must be considered and the functional and engineering requirements
must be documented, reviewed, and approved.
FDA guidance says to include
Functional requirements—what the device does
Performance requirements—how well the device performs
Interface requirements—compatibility with external systems
One way to look at design inputs is that this is the first manifestation of what the company’s mar-
keting claims will look like years later when the product is approved and commercially released.
The user needs and benefits built into the design inputs are the very things the company will want
to tout in the commercial environment.
(2) Design output
This section of the design controls regulation essentially includes the specifications that define
the medical device. The output is the package of documentation that is used to clear the product
with FDA and to manufacture it.
The manufacturer must establish and maintain procedures for defining and documenting the
output. The QSR states:

Design output procedures shall contain or make reference to acceptance criteria and shall ensure that
those design outputs that are essential for the proper functioning of the device are identified.
Id. § 820.20(d).

The output contains things such as
• Design specification
• Testing against standards, such as biocompatibility, toxicity, and electrical