In May 2026, FDA finalised "Content of Human Factors Information in Medical Device Marketing Submissions", replacing the December 2022 draft (Federal Register notice). In August 2026, it issued a revised version of "Applying Human Factors and Usability Engineering to Medical Devices", first issued on 3 February 2016.
The two documents now work as a pair. One covers how to do human factors work; the other covers what to put in a 510(k), De Novo, PMA or HDE. This article explains what each does, the four decision points that set the HF Submission Category, and what that means for software.
Two guidance documents, two jobs
| Guidance | What it covers | Current version |
|---|---|---|
| Applying Human Factors and Usability Engineering to Medical Devices | The human factors and usability engineering process: definitions, analyses, formative evaluation and validation testing | Final, August 2026 (first issued February 2016) |
| Content of Human Factors Information in Medical Device Marketing Submissions | Which human factors information to include in a marketing submission, by HF Submission Category | Final, May 2026 |
Source: FDA guidance pages.
FDA describes the Content guidance as a companion to the Applying guidance. Both are guidance: they do not establish legally enforceable responsibilities, and "should" means recommended.
In our view, read them in order. The Applying guidance tells you what work to do; the Content guidance tells you how much of it to submit.
When the Content guidance applies
The Content guidance covers 510(k)s, De Novo requests, PMAs and HDE applications. It notes that combination products may raise additional human factors questions, which other FDA guidance covers.
FDA expects that industry and FDA may need at least 60 days to put the guidance into practice. For submissions pending at publication, and those received before 1 August 2026, FDA generally does not expect the newly recommended information, although it will review it if provided.
The key terms
The Applying guidance defines the terms the decision points rely on:
User interface: the means by which the user and the device interact. FDA's examples include packaging, labelling, training materials, physical controls, display elements and alarms, not only a screen.
Use error: a user action, or lack of action, that was different from what the manufacturer expected and caused a result that was different from what the user expected, was not caused solely by device failure, and did or could result in harm.
Critical task: a user task which, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user, including compromised medical care.
Use-related risk analysis (URRA): systematic use of available information to identify use-related hazards and estimate use-related risk.
In our view, the URRA drives everything that follows. Without it, you cannot answer the decision points.
The four decision points
Section IV of the Content guidance sets four decision points.
| Decision point | Question | Outcome |
|---|---|---|
| A | Is it a modification to an existing device? | No (new device): go to C. Yes: go to B |
| B | Is there a change to the user interface, intended users, intended uses, use environments, training or labelling? | No: Category 1. Yes: go to C |
| C | Based on the URRA, are there critical tasks (new device), or new or impacted critical tasks (modified device)? | No: Category 2. Yes: go to D |
| D | Considering history of use, interface complexity and existing risk controls, should validation test data be submitted? | No: Category 2. Yes: Category 3 |
Source: Content guidance, Section IV.
Some details matter in practice:
Decision Point A: a new device can be treated as a modification if it has the same or similar user interface as one of the manufacturer's own legally marketed devices and leverages that device's human factors information.
Decision Point C: for a modified device, FDA recommends looking at the URRA for the whole finished device, not just the change, and considering cumulative changes.
Decision Point D: FDA says validation data are likely needed for complex user interfaces and for device types with known use error issues, such as infusion pumps. It may also ask for them where there is a significant difference from similar devices, a new safety signal linked to use error, or an increase in the severity of possible harm.
What each category submits
| Category | What to submit |
|---|---|
| 1 | A conclusion and high-level summary, including a statement that the modifications do not affect human factors considerations |
| 2 | Category 1 content plus descriptions of users, uses, use environments and training, the user interface and known use problems, the URRA and critical tasks, and a rationale for why the answer at C or D is "No" |
| 3 | A full HFE/UE report, adding preliminary analyses and evaluations and human factors validation testing of the final design |
Source: Content guidance, Section IV and Table 1.
FDA recommends that manufacturers keep human factors information in the design and development file whether or not it is submitted, referring to 21 CFR 820.10(c) and ISO 13485:2016 subclause 7.3. Our article on 21 CFR Part 820 covers the QMSR.
Software: algorithm changes and screen changes
Example A.1 in the Content guidance covers a cleared computer-assisted detection device for gastrointestinal lesions. The manufacturer changes only the detection algorithm, with no change to the user interface, users, uses, environments, labelling or training. The answer at Decision Point B is "No", so the submission falls into Category 1.
Hypothetical example: a Dutch company has a 510(k)-cleared image-analysis app for clinicians.
Release 2 changes only the algorithm. As in Example A.1, the answer at B is "No", so Category 1 applies.
Release 3 redesigns the results screen. The answer at B is now "Yes". The category depends on the URRA at C and, if critical tasks are affected, the assessment at D.
In our view, software teams should record the decision points for every release, even when the result is Category 1. Our article on software as a medical device covers the wider framework.
When to use a Pre-Submission
FDA suggests a Pre-Submission if you are not sure whether a rationale in place of validation testing would be appropriate. In our view, this is most useful at Decision Point D, where the answer depends on judgement about complexity, history of use and risk controls.
Conclusion
FDA's human factors guidance is now two final documents. The Applying guidance sets the process, and the Content guidance sets what to submit, through four decision points and three HF Submission Categories. For submissions received from 1 August 2026, FDA expects the new content.
In our view, the order of work is simple: complete the URRA, walk through the decision points, record the result in the design file, and only then write the human factors section of the submission.
If you need help planning a US submission, our regulatory strategy team can help, or contact MedQAIR.
Frequently asked questions
Is the Content guidance still a draft?
No. FDA finalised it in May 2026, replacing the December 2022 draft.
Is FDA human factors guidance mandatory?
No. Both documents are guidance and do not establish legally enforceable responsibilities. Design controls under 21 CFR Part 820 still apply.
Does an algorithm-only change need human factors data?
In FDA's Example A.1, an algorithm change with no change to the user interface, users, uses, environments, labelling or training falls into Category 1, which needs only a conclusion and high-level summary.
Does Category 1 mean no human factors work?
No. It sets what to submit, not whether to assess use-related risks. FDA recommends keeping the supporting information in the design and development file.
When should human factors validation data be submitted?
When the answer at Decision Point D is "Yes" (Category 3). FDA says this is likely for complex user interfaces and device types with known use error issues.
