Design Controls (Part 6): Design Changes

Design Controls (Part 6): Design Changes

September 19, 2019 | Posted by Ben Trombold

In a design-controlled project, no changes can be made to an approved design without the change being taken through the entire design process. Be aware of the following two factors when implementing any change:

Document control – you have to document each version and track their status in the DHF (have they been verified, validated? Has the risk management file been updated?). Who will sign off on the new version of the document? How do we assure that everyone is using the new document – but only after it is approved and has taken effect?

Change Control – what is the change? How will it affect the overall system? What are the additional risks introduced? How do you assure through regression testing that the change doesn’t initiate other problems? How will the difference be verified or validated? What changes to the production specifications, packaging, and labeling are necessary?

The timing of a design change is critical. Changes that are implemented early in the design process are often easily handled. Changes late in the process, especially after design transfer, can create as much time and effort in repeating verification and validation activities as implementing the actual change.

Because of the high cost of late changes, consider reserving requested changes for future versions of the product, unless the change is required to correct an error, mitigate a user hazard, or reduce a security vulnerability.


Design History File

The DHF is a compilation of records that describes the design history of a completed device. The DHF demonstrates that the design was developed in accordance with the approved design plan, and includes all documentation of the design process described above. It is vital that medical device manufacturers have the necessary information in the DHF to be able to support the device throughout the device’s life cycle adequately.

For software specifically, it is crucial that a manufacturer possesses compiled software for each device as well as the source code necessary to reproduce the compiled software. Make sure that you own all of the design materials so that you can continue to support your device when staff and subcontractors move on to other things and are no longer accessible.

This concludes our blog series on the Design Control process. If you’d like to learn more or are considering partnering with us, please email us at!



Get Started On Your Next Project