For years, the Association for the Advancement of Medical Instruments (AAMI) and the American National Standards Institute ANSI/AAMI HE75 human factors standard was a document that human factors professionals referenced for medical device design principles but largely set aside when it came to usability testing. By the time most practitioners entered the field, its guidance on testing practices was already outdated, overtaken by evolving FDA expectations, reviewer feedback, and hard-won industry experience. That has changed.
The 2025 update to HE75 is the most significant revision in over 15 years, and for the first time, it “puts on paper” much of what experienced practitioners and regulators have long expected but never formally codified.
This matters whether you are a large strategic manufacturer iterating on an established device platform, a mid-stage company with a technology approaching design freeze, or a startup preparing for your first validation study. Anytime usability testing is required, for new devices or modifications, in the U.S. (FDA) or under MDR and other global regulations, HE75:2025 is now the primary human factors reference to build from.
Here is what changed, what it means, and what to do about it.
In practical terms, what is HE75:2025? It is AAMI’s human factors engineering standard that provides guidance on how to apply human factors engineering throughout the medical device development process.
The 2009 edition of HE75 described where usability activities should occur in the product development process and what outputs to expect. The 2025 edition of the ANSI/AAMI HE75 human factors engineering standard goes further. It aligns the standard with the current regulatory landscape: FDA Center for Devices and Radiological Health (CDRH) guidance, Human Factors Studies and Related Clinical Study Considerations in Combination Product Design and Development, AAMI TIR59, and the international usability engineering standard IEC 62366-1:2015.
In practice, FDA sets the most stringent expectations for human factors engineering (HFE) in the medical device industry. Meeting these requirements positions your HFE program for smoother submissions in other global markets. While that has always been directionally true, the updated standard now spells out how to meet those FDA expectations more explicitly.
Terminology has been updated to match current regulatory usage. What was referred to as "use-error risk analysis" in 2009 is now termed "use-related risk analysis" (URRA). While the 2009 edition of HE75 recommended selecting tasks for assessment based on risk estimation and including “essential tasks” based on frequency, importance, urgency, or difficulty, the updated standard directs that tasks for human factor validation testing be selected based on severity of potential harm alone. Under the revised framework, the updated HE75 defines “critical tasks” as user tasks that, if performed incorrectly or not performed at all, would or could result in serious harm, and specifies that these should be the primary focus of human factors validation testing.
Non-critical tasks may still need to be performed as part of the hazard-related use scenario to allow the participant to interact with the device as naturally as possible; however, they need not be scored (though it might certainly serve you if reviewers later question the assigned severity rating). The update also adds two entirely new chapters addressing combination products (auto-injectors, inhalers, and similar devices) and integrated systems, reflecting the reality that modern medical devices are increasingly digital and interconnected.
The most immediate impact is confidence. Until now, many of these testing practices existed only as unwritten expectations. Teams learned what reviewers wanted through FDA feedback letters or, at best, through pre-submission meetings. Individual reviewers often had different expectations, and manufacturers had limited ability to point to a consensus standard to support their approach. HE75:2025 changes that. When a reviewer questions your human factors study design, you now have a concrete, consensus human factors standard to reference.
One of the most valuable additions in HE75:2025 is a high-level mapping of human factors activities within design controls, aligned with AAMI TIR59. The new HFE process section defines which deliverables belong in the usability engineering file per IEC 62366, specifies which serve as inputs to the design control process, and includes URRA updates and usability testing as part of post-market surveillance. Follow that map and you have a defensible, well-structured program from formative evaluation through summative validation.
Section 9 on usability testing in HE75:2025 is where many of the most practical changes live. These updates codify practices that experienced professionals already follow, but seeing them in a consensus standard for the first time is significant. The updates address participant selection and user group consolidation rationale, team simulations for complex multi-user devices, and training approaches including train-the-trainer models and minimum training decay periods. They also cover study design and the inclusion of non-critical tasks for simulation realism, expanded post-test interview protocols for root cause analysis, and updated sample size recommendations. For those designing validation studies involving devices used by surgical teams, in interventional settings, or across multiple user populations, these provisions add welcome clarity for FDA/EU MDR submissions.
For example, medical devices where a clinical representative will be present to monitor every instance of product use in the field. The updated standard recommends asking them not to intervene unless the study participants ask, in order to simulate the minimum level of support that a user might receive in the field.
The standard also now explicitly recommends conducting a pilot test: a late-stage formative evaluation using the validation protocol at reduced sample size with production-equivalent devices. This may feel like an added step that elongates the timeline. In practice, pilot testing, often paired with a pre-submission meeting, almost always compresses the overall pathway to regulatory approval by catching problems before they become formal findings.
Regardless of company size or development stage, incorporate HE75:2025 into your human factors engineering and usability testing design now. For most teams, the standard's influence will be felt most directly in the use-related risk analysis and in formative or summative test protocols.
If you are early in development, use the new HE75:2025 HFE process map as your framework. It lays out which human factors activities should occur at each stage of product development and what deliverables regulators expect. Following it from the start will set you up for a smoother path and help you avoid the costly experience of learning what reviewers expect only after you have submitted.
If you are mid-development and approaching design freeze, pressure-test your URRA. The standard reinforces that task selection for validation must be based on a comprehensive use-related risk analysis, and this is where we see teams run into the most trouble. Creating well-defined use scenarios and identifying critical tasks takes deliberate time. Certain tasks with high severity can be rationalized out of testing if a risk control measure has genuinely “designed out” the hazard, or if a warning is not specific to the device. But those decisions require careful thought and documentation. A thorough URRA will alleviate significant trouble downstream.
If you are nearing submission, strongly consider a pilot test aligned with an HE75:2025 usability testing strategy. It provides a final opportunity to identify residual use-related risks and refine your test protocol before committing to the full validation study. Pair it with a pre-submission meeting and you carry far more confidence into the process.
HE75:2025 gives you more clarity, more structure, and more confidence than any prior version. But none of that helps if your use-related risk analysis is not up to snuff. The URRA is the foundation. It drives your task selection, your use scenarios, and ultimately what you present to participants in validation. If it is incomplete, too narrow, or insufficiently thought through, the rest of your program is built on unstable ground, no matter how well your study protocol follows the new standard.
Create the time to do your URRA well. It is the single highest-leverage activity in your human factors program. Our Human Factors team can get you there faster, adding velocity to your vision. Get in touch today.
Human Factors Engineering at Veranex ensures your device can be used safely and intuitively in the real world, not just in a lab. Building on early Research & Strategy, our specialists can access designers and engineers throughout development, running formative and summative studies aligned to IEC 62366, FDA, and global regulatory expectations, including AAMI/ANSI HE75:2025. Usability findings feed directly into design refinements, quality systems, labeling, training materials, and Clinical Research planning, so pivotal trials are not derailed by avoidable use errors. When integrated with Regulatory Affairs and Medical Writing, Human Factors evidence becomes a strength in submissions and post-market risk management, protecting patients, timelines, and budgets simultaneously.
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