Misconceptions Regarding “Design Controls”

Introduction

Since the 1980s, the FDA has imposed stringent regulations on “design controls.” The fundamental reason is that even if a medical device is manufactured correctly in a production facility according to design specifications, if the design itself is flawed, the resulting device cannot be safe. Currently, a substantial portion of device failures in the marketplace stem from design-related issues, and within this category, a significant proportion involves software defects. In the author’s experience providing consultations to medical device companies, design departments frequently misunderstand, lack clarity about, or are simply unaware of “design controls.” This article addresses the distinction between “design” and “design controls,” the essence of design control, and practical considerations for implementation.

“Design” and “Design Controls” Are Different

First and foremost, “design” and “design controls” are distinct concepts. What the FDA and ISO 13485 require and regulate is not “design” per se, but rather “design controls.”

Naturally, if a company cannot perform “design,” it cannot manufacture devices—hence every company necessarily implements design activities. Regulatory requirements do not dictate how specifications should be written or how drawings should be created. Therefore, design engineers are frequently asked questions about how to write design documents, specifications, or verification plans; in essence, these approaches are flexible and may vary by company.

However, regulatory requirements and international standards do mandate that manufacturers create a design and development plan at the outset, and throughout each design stage, implement “design controls” in compliance with that plan. “Design controls,” in essence, means managing the entire design process in a planned manner, appropriately documenting the process, and systematically implementing reviews and approvals at each stage.

In current practice, design controls at many medical device companies appear to be implemented inadequately. Specifically, the design and development plan must define design inputs (user needs, regulatory requirements, integration with risk management, and other criteria), and must detail at which stages design reviews will be conducted, by whom, and how verification and validation activities will be performed. However, in reality, many companies fail to create sufficiently detailed and comprehensive design and development plans, do not revise such plans appropriately, and often do not adhere to them consistently during the design process.

It should be noted that most Class I medical devices are not subject to design control requirements. However, if a Class I device incorporates software, design controls do apply—this distinction requires careful attention. This requirement is being further strengthened through the FDA’s Quality Management System Regulation (QMSR) revision currently underway from 2024 through 2026, wherein design control requirements will be harmonized with ISO 13485:2016.

The Purpose of “Design” Is to Enable “Manufacturing”

Next, the purpose of “design” is to enable “manufacturing.” This principle is self-evident: since we design in order to manufacture, process design is also included within the scope of “design.”

Accordingly, records pertaining to process design must also be subject to design review and retained in the Design History File (DHF). Design change management is a critical element of design controls, and in essence, design changes are manufacturing changes. Stated another way, a design change that does not result in any change to manufacturing is not feasible.

Design changes must follow the process specified in 21 CFR 820.30(i) and ISO 13485 Section 7.3.9: identification of the need for change, documentation, verification or validation (or verification alone, where appropriate), review, approval, and implementation. Particular attention must be paid to the fact that when a design change to a previously cleared medical device (via 510(k)) significantly impacts the device’s safety, effectiveness, or intended use, a new 510(k) submission may be required.

“Labeling” Is Also an Output of Design

“Labels” and “labeling” are design outputs and must be subject to design review. Records of labeling activities must be retained in the DHF. It is important to note that “labels” are a subset of “labeling.”

“Labeling” encompasses all written, printed, graphic materials, and displays that patients or users encounter. From the perspective of FDA regulations and ISO 13485, labeling includes: instructions for use (including abbreviated versions), regulatory labeling or package insert, package markings and labels, service manuals, training materials, catalogs, exhibition materials, product information on websites, product videos, software user interface displays (in the case of Software as a Medical Device—SaMD), and essentially all formats through which product information is conveyed.

These materials must be appropriately designed, reviewed, and approved. However, a distinction that is sometimes difficult to draw is where “advertisement” ends and “labeling” begins. Material containing only product numbers and pricing would generally be considered advertising. Conversely, material making claims regarding the benefits, effects, or medical benefits of a device would certainly constitute labeling. Among materials encountered by patients or users, items that do not constitute labeling include, for example, shipping documents.

FDA 21 CFR Part 801 establishes general labeling requirements for medical devices, mandating the inclusion of manufacturer name and address, instructions for use, warning statements, and Unique Device Identifier (UDI) information. Given that labeling deficiencies are among the leading causes of medical device recalls, design-stage review, approval, and documentation of labeling are critically important.

“Packaging” Is Also an Output of Design

Packaging is an output of design and therefore must be subject to appropriate design controls and design review, with records retained in the DHF.

For precision mechanical devices in particular, packaging design is critically important. A medical device packaging system must function to protect the device from the point of manufacture through the point of final use. Appropriate validation testing must demonstrate that the packaging and cushioning materials adequately protect the device from impacts, vibrations, and other stresses encountered during distribution. For example, conducting validation tests such as dropping a packaged product from a height of 90 centimeters represents an industry-standard practice.

Packaging validation should be performed in accordance with the ISO 11607 series standards: ISO 11607-1 (Requirements for materials, sterile barrier systems, and packaging systems) and ISO 11607-2 (Validation requirements for forming, sealing, and sterile barrier system processes). These standards are FDA-recognized consensus standards and harmonized standards under the EU Medical Device Regulation (MDR).

Key elements of packaging system validation include: (1) material qualification and testing; (2) integrity testing of sterile barrier systems; (3) shipping simulation testing (such as ASTM D4169); (4) shelf-life testing; and (5) usability validation (confirming aseptic opening performance). Incorporating planning for these validation activities at the design stage is an essential requirement for ensuring safety and effectiveness.

Conclusion

Design controls represent not merely a documentation or procedural requirement, but an essential process for ensuring the safety and effectiveness of medical devices. Understanding the distinction between “design” and “design controls,” creating and rigorously adhering to a comprehensive design and development plan, clarifying design inputs and outputs, conducting design reviews at each stage, and appropriately managing all design outputs—including design changes, labeling, and packaging—are mandatory for medical device companies. Only through these systematic activities is it possible to develop and provide medical devices that are safe and effective for patients and healthcare professionals.