FDA Revises Human Factors Guidance to Match 2026 Submission Guidance

The FDA on Monday issued a revised version of its main guidance on applying human factors and usability engineering to medical devices, the agency's core document on designing device user interfaces to reduce use errors that could cause harm.

The revised guidance, from the Center for Devices and Radiological Health, replaces the version issued on February 3, 2016. According to its guidance history, the FDA made the changes under Level 2 guidance procedures. It updated the definitions and Section 9, on documentation, for consistency with a companion final guidance, Content of Human Factors Information in Medical Device Marketing Submissions, and deleted an appendix. The FDA's guidance database lists that companion document as issued on May 29, 2026. Comments on the revised guidance can be submitted at any time under docket FDA-2011-D-0469.

How the two documents fit together

The FDA describes the May guidance as a risk-based framework for deciding what human factors information should be documented and included in 510(k)s, De Novo requests, premarket approval applications and humanitarian device exemption applications, and says it is intended as a companion to the guidance revised Monday. The revised guidance itself points manufacturers to the May document for what to include in a marketing submission, while it covers the engineering process.

The revised guidance also reflects the agency's amended device quality rule. It notes that the Quality Management System Regulation, which incorporates the international standard ISO 13485:2016 by reference, took effect on February 2, 2026.

What the guidance recommends

The guidance focuses on the user interface, which it says includes all points of interaction between a device and its users, such as displays, controls, packaging, labels and instructions for use. It says the FDA's main concern is that devices are safe and effective for intended users, uses and use environments, rather than ease of use or user satisfaction.

Because the probability of use errors is very difficult to determine, the FDA says the severity of potential harm is more meaningful in deciding whether a hazard must be designed out. If risk analysis shows use errors could cause serious harm, manufacturers should apply human factors processes, including when modifying a marketed device to correct use-related design problems.

The document defines a critical task as one that, if performed incorrectly or not at all, would or could cause serious harm to the patient or user, including compromised medical care. It describes preliminary analyses to identify such tasks, steps to eliminate or reduce use-related hazards, and human factors validation testing at the end of development, including simulated-use and actual-use testing and testing of modified devices.

On validation testing, the guidance says that in general the minimum number of participants should be 15, and that devices with more than one distinct user population, such as lay users and health care providers, should be tested with at least 15 participants from each. It notes the recommended minimum could be higher for specific device types.