When developing a medical device for the U.S. market, the Instructions for Use (IFU) is more than just a user manual—it’s a regulatory document subject to detailed review by the FDA. A well-structured IFU plays a central role in demonstrating your product’s safety, proper use, and compliance with labeling regulations.

For U.S.-based manufacturers, aligning your IFU with both international standards and FDA-specific requirements is critical—not only for successful submission, but also for mitigating product liability and ensuring user safety.

This article outlines the four key standards and regulations that your documentation team should be familiar with when preparing IFUs for FDA approval. It also highlights how each standard applies to different aspects of IFU content, structure, and safety communication.

1. ISO 20417: What Information Must Be Included in the IFU?

ISO 20417:2021 defines the globally accepted list of essential information that must be included in the IFU and labeling for medical devices. This includes:

• Product name and model
• Manufacturer details
• Intended use
• Contraindications, warnings, and precautions
• Sterilization method
• Storage and handling conditions
• Reuse limitations or instructions

For example, in diagnostic imaging devices like ultrasound systems, the IFU must clearly state probe compatibility, cleaning instructions, clinical indications, and limitations of use. ISO 20417 serves as the foundation for ensuring that no critical information is omitted.

This standard answers the question: “What content is required?”

2. IEC 82079-1: How Should That Information Be Structured?

While ISO 20417 defines what to include, IEC 82079-1:2019 provides guidance on how to organize and present that information for optimal usability. It emphasizes:

• Logical information flow aligned with user tasks
• Modular structure for clarity and reuse
• Use of consistent terminology
• Visual aids and warning placements that match procedural steps

For example, in professional-grade energy-based aesthetic devices, such as RF or IPL systems used in dermatology clinics, IEC 82079-1 helps ensure that step-by-step procedures, device settings, and safety notices are clearly structured and placed in line with user actions.

This standard answers the question: “How should it be presented?”

3. 21 CFR Part 801: What Does U.S. Law Require?

21 CFR Part 801 is the FDA’s legally binding labeling regulation. Any IFU submitted to the FDA must comply with this part of the Code of Federal Regulations (CFR). Key requirements include:

• The IFU must be in English
• Wording must be clear, factual, and not misleading
• Warnings must be included to prevent foreseeable harm
• Specific content may be required depending on device class

For example, wearable blood pressure monitors must include clear instructions on proper placement, how to interpret readings, battery safety, and connectivity to companion apps. The language must be understandable to the intended user—often a layperson.

This regulation defines the legal baseline for FDA-compliant documentation.

4. ANSI Z535.6: How to Structure Safety Messages Correctly

ANSI Z535.6 is a U.S. standard focused on how safety messages should be written and formatted in manuals and IFUs. It establishes standardized formats for conveying hazards using four key components:

• Signal Word (e.g., WARNING, DANGER, CAUTION)
• Hazard Description
• Avoidance Instructions
• Consequence of Not Avoiding

For example, an AI-powered software-based medical device (SaMD) that assists with diagnostic decisions must clearly communicate its intended use—such as supporting, not replacing, clinical judgment. ANSI Z535.6 helps structure such warnings using standardized language, especially when improper use could lead to patient harm or misdiagnosis.

This standard defines how to communicate risk in a legally defensible way.

5. Translation Considerations: If You’re Also Localizing

If your device will be used in multilingual environments (e.g., hospitals with Spanish-speaking patients) or submitted internationally, be aware of the following:

• Use Plain Language for end-user comprehension
• Follow a structured QA process based on ISO 17100 for translation quality
• Assign translators with medical domain knowledge
• If using ISO 15223-1 symbols, include accompanying text explanations per FDA expectations

Even when English is the primary language, clarity and consistency are critical. FDA reviewers will not correct unclear language—they will send it back.

Translation is not just a language task—it’s a compliance task.

Final Thoughts: IFUs Are Regulatory Assets

Preparing an IFU for FDA submission requires more than good writing. It demands a deep understanding of applicable standards, user safety principles, and regulatory expectations. To succeed, documentation teams must blend:

• Content completeness (ISO 20417)
• User-centered design (IEC 82079-1)
• Legal compliance (21 CFR)
• Safety clarity (ANSI Z535.6)

At Hansem Global, we support U.S. medical device manufacturers with end-to-end IFU development, technical writing, and regulatory translation services—helping ensure your documentation is not just clear, but compliant and submission-ready.