Medical Device Design Controls

This article provides an overview of FDA design controls and lists resources to help understand and apply them.
This is in a “dry” format, necessary for repeating definitions. See my blog for versions that use case-studies or are related to pop culture.

5 minute read.


BACKGROUND

Researchers in the 1980’s discovered that 44% of medical device recalls in the United States could have been prevented through design controls. In other words, almost half of medical device recalls were preventable before a product was manufactured.

The risk to patients and cost to American medical device companies was addressed by the United States Food and Drug Administration. The FDA worked with industry experts to understand best-practices for effective and efficient design, adding Design Controls to recommended guidelines.

In 1997, these guidelines became the FDA Quality System Regulation (QSR), a law under theCode of Federal Regulations, Title 21, part 820 (21 CFR 820).


OVERVIEW

FDA laws apply to any manufacturer of medical devices or pharmaceuticals selling products in the United States. Design Controls are one subsystem of a required Quality System.


Ten Things

Design Controls have ten components listed in 21 CFR 820.30. This is my attempt to paraphrase legal-esque sounding requirements; always refer to original, official regulations when making decisions.
Several words are used for different meanings, such as “requirements” and “inputs.”  Don’t get caught on words, and don’t assume each use means the same things. Try to understand the concept of what’s required for each component.

General Requirements
21CFR820.30 (a)

  • In the United States, design controls are required for all manufacturers of class Class II and Class III medical devices, and a few Class I devices.
  • Design Controls are not required when researching new ideas. Design Controls begin, and must be documented, when a company commits to developing a product.
  • The distinction between research and development should be defined in each company’s Quality System.

Design & Development Planning 21CFR820.30 (b)

  • Create and follow a development plan.
  • Describe all responsibilities, timelines, ways to find more information, and when and how to update the plan.
  • Plans should be clear, easy to follow, and accurate by updating throughout the design project using a team-driven process. An effective plan could be followed by anyone, not just your team.


Design Input
21CFR820.30 (c)

  • Inputs are what needs to be accomplished by a design. At a minimum, design inputs must include user needs and regulatory requirements. Some companies include business needs.
  • User needs often ambiguous terms like “lightweight” or “easy to set up,” and are refined by a company into requirements that are unambiguous and able to be measured by a test, like “less than 0.75 lbs” or “able to be set up within 30 seconds by untrained users.”
  • User needs include risk, which must be constantly reaccessed as a design progresses.
  • Inputs are agreed upon, in writing, by people listed in your plan.

User Needs

Regulatory Requirements


Design Output
21CFR820.30 (d)

  • Outputs are design features that satisfy inputs, such as drawings of parts, software code, operating procedures, product labels, etc.
  • Outputs are reviewed and agree upon, in writing, by people listed in your plan.

drawings, software, test methods, etc.


Design Review 21CFR820.30 (e)

  • Reviews ensure plans are followed and updated using a team-driven process.
  • Reviews shall have at least one person attending who does not have responsibility for the stage of your plan being reviewed.
  • At the least, design reviews authorize the design inputs, and that outputs satisfy the inputs through verification and validation testing.
  • Reviews are approved, in writing, by people listed in your plan.

Design Verification 21CFR820.30 (f)

  • Verification compares outputs to Input requirements.
  • Verification must be measurable. For example, if a user need is for a “light weight” product, and the requirement is under 0.75 lbs, a verification test would be weighing the product to ensure it’s under 0.75 lbs. If a requirement is “less than 9 cm long,” verification could be simply referencing part dimensions on the design output.
  • Verification is reviewed and approved, in writing, by people listed in your plan.

Design Validation
21CFR820.30 (g)

  • Validation ensures Inputs are met for output that must be sampled statistically rather than measured directly. For example, measuring a mass-produced chemical wouldn’t be practical, output can tested using samples and validating consistency through statistics.
  • Validation also ensures user needs are met from the user’s perspective. For example, if an Input is that a package “must be opened within 30 seconds” the final design couldn’t be measured directly, it must rely on real-world people in a controlled test.
  • Validation statistics must be true, which means that often post-market surveillance must measure results and compare them to assumptions used for design validation, updating validation statistical requirements such as the sample size.
  • Validation must use production-units in actual or simulated conditions.Validation is reviewed and approved, in writing, by people listed in your plan.


Design Transfer
21CFR820.30 (h)

  • Ensure that you can transfer a design to manufacturing without losing control of outputs that were verified and validated.
  • Transfer is reviewed and agreed upon, in writing, by people listed in your plan.

Design Changes 21CFR820.30 (i)

  • Changes to inputs, outputs, and verification or validation methods must be controlled ensure there aren’t unforeseen consequences, including for other products that may share design components.
  • Changes are reviewed and agreed upon, in writing, by people listed in your plan.


Design History File
21CFR820.30 (j)

  • A Design History File (DHF) is evidence that a product was developed according to a Plan, starting with user needs, and referencing all inputs, outputs, verification, validation, and transfer procedures.
  • The DHF is maintained for the life of a product, including future improvements and risk reductions.
  • I emphasize that a DHF should include “why” changes are made so that future teams learn from current teams. This has been critical in addressing device recalls and designing improvements.


Miscellaneous

Reducing risk is an assumed user need, which is why design inputs include requirements for reducing risk. Design controls assume that teams document risk-assessments throughout development. Highly effective companies use high-level risk plans that span multiple departments, ensuring that information about patient safety is shared with, and can be implemented by, departments such as design, purchasing, manufacturing, shipping, etc.
Historically, a waterfall-diagram has been used to illustrate Design Controls.

Most companies don’t follow a waterfall-method for development. Design activities occur simultaneously, often across different teams that may reside in multiple states or countries. Modern companies also strive for concurrent-design between teams, such as development and manufacturing.

Design Controls may be simplified to documenting a process of creating and following a plan, focusing user needs and regulatory requirements to create inputs, facilitating communication between teams using change procedures & reviews, ensuring outputs satisfy Inputs through verification and validation prior to transfer, and documenting your process in a Design History File that includes assessments of risks and mitigations in both design and manufacturing.
Design Controls extend into manufacturing and throughout the life of a product. Feedback from manufacturing and post-market surveillance becomes input for future design changes.


RESOURCES

The FDA is a transparent organization. To paraphrase The Buddha, there isn’t a secret “hidden in the closed fist of the teacher,” meaning there isn’t a game where only one person knows the rules. The FDA tells you exactly what they require and tries to help you accomplish it.
The resources below are focused on medical devices and Design Controls.
FDA OFFICIAL INFORMATION
FREE TRAINING

TRAINING & CONSULTING COMPANIES


SUMMARY

Design controls are laws to protect patient safety and facilitate efficient companies. Design Controls are a part of the FDA Quality System Regulations.Design Controls can be summarized as: Focus on solving user needs, follow a plan, ensure communication via design reviews, verify and validate that designs meet user needs, oversee successful transfer to manufacturing, and document all designs and changes in a Design History File.
FDA design controls are one part of selling medical devices in the United States. To sell in other countries requires additional requirements, including a comprehensive quality control system that meets FDA Quality System Regulations and the International Standards Organization standards in ISO 13485, plus each country’s specific requirements.
Good luck!