What design validation proves
Design validation proves that the finished device meets user needs and its intended use, in the hands of real users and in real or simulated conditions. Verification asks whether you built the device right; validation asks whether you built the right device. FDA’s QMSR training frames validation as “Device meets the requirements for the intended use” and “I made the correct device” (FDA, QMSR Design and Development).
A device can pass every verification test and still fail validation: a correct alarm that nurses cannot hear, a correct dose screen users misread, or a correct algorithm that does not fit the clinical workflow.
For how validation differs from verification, with checklists for both, see Design Verification vs Design Validation: Medical Device Checklists for 2026.
What the requirements say
Since February 2, 2026, ISO 13485:2016 clause 7.3.7, incorporated into the QMSR, governs design validation in the US. FDA summarizes that validation:
- “Shall be performed per documented plans and procedures to ensure the device meets its intended use”
- documents “methods, acceptance criteria, and statistical techniques”
- must “be conducted on representative product”
- includes clinical evaluations that “meet applicable regulatory requirements”
- “Must be completed prior to release”
Source: FDA, QMSR Design and Development. The QMSR training also lists “Design and Development Software Validation” as a separate element FDA evaluates during baseline inspections (FDA, QMSR inspections).
The evidence that makes up validation
| Evidence type | What it shows | Typical source |
|---|---|---|
| Human factors (usability) validation | Intended users can perform critical tasks safely in the intended environment | Simulated-use study with representative users |
| Clinical evidence | The device achieves its clinical purpose | Clinical study, literature, clinical evaluation |
| Software validation | Software meets user needs and intended use in the system context | System-level testing, use scenarios |
| Simulated or actual use testing | Performance under realistic conditions | Bench simulations, animal or cadaver models where appropriate |
| Labeling and instructions | Users can follow instructions as written | Human factors study tasks, comprehension testing |
All validation must use production-equivalent units, or the file must justify differences.
What changed in 2026: FDA’s final human factors guidance
On May 29, 2026, FDA finalized “Content of Human Factors Information in Medical Device Marketing Submissions,” replacing the December 2022 draft (FDA Law Blog). It sorts submissions into three categories:
| Category | What to submit |
|---|---|
| 1 (modified devices only) | Conclusion and high-level summary of the HF evaluation |
| 2 | Rationale for why there are no critical tasks, or no new or impacted critical tasks |
| 3 | Full HF engineering report, including HF validation testing |
The final version adds a new Decision Point D, which considers user interface history, complexity and existing risk controls to decide whether validation test data must be submitted. Emergo by UL notes that “not all devices with new or impacted critical tasks automatically require additional HF validation testing” and that manufacturers “may, in some cases, provide a robust justification in lieu of new validation data” (Emergo by UL).
The catch: FDA recommends keeping HF information “regardless of whether it is submitted to FDA,” and reviewers may still request it (FDA Law Blog). Less submitted data means the justification in your design file must be stronger, not weaker.
What FDA cites in validation
- Criteria set after testing. FDA found a firm’s software “Test plans do not include established acceptance criteria prior to testing,” and that security testing for an ultrasound system found risks the file did not resolve (FDA warning letter, Contec Medical Systems, October 2025).
- Missing test plans in the design file. The same letter states the firm “did not have the software Test Plans” for a cleared ultrasound system.
- Validation that ignores manufacturing reality. In January 2026, FDA concluded a glucose monitor maker “has not adequately validated its manufacturing and release controls, as required by 21 CFR 820.30(g)” (FDA warning letter, Abbott Diabetes Care).
Both inspections predated the QMSR; the expectations carry over to clause 7.3.7.
How to plan design validation
- Write user needs that can be validated, with intended users, environments and uses named.
- Run a use-related risk analysis to identify critical tasks early.
- Choose evidence types (human factors, clinical, software, simulated use) per user need.
- Approve protocols with acceptance criteria before any session or study starts.
- Use representative product and users, including labeling and training as shipped.
- Document residual use errors and whether further risk controls are needed.
- Decide the FDA HF submission category and record the rationale, even if no data is submitted.
- Complete validation before release and file reports in the design and development file.
Design validation checklist
- Validation plan maps every user need to evidence
- Use-related risk analysis identifies critical tasks
- Protocols approved with acceptance criteria before testing
- Representative users, environments and production-equivalent units
- Labeling and instructions validated as shipped
- Software validated at system level, including security risks
- Clinical evidence meets applicable regulatory requirements
- HF submission category and rationale documented per the May 2026 guidance
- Validation completed before release
- Results traced to user needs and risk controls
Check the validation file before FDA asks for it
With FDA’s new guidance, more validation evidence will stay in the design file instead of the submission, and reviewers can still ask for it. AskDona reviews validation plans, HF reports and justifications against ISO 13485 clause 7.3.7, FDA guidance or your own procedure, flags missing criteria, weak rationales and untraced user needs, and cites the passage behind every finding.
Run a sample validation file assessment on one HF report or validation plan. AskDona shows the evidence; your teams decide.
FAQ
What is design validation? Objective evidence that a device meets user needs and its intended use, tested on representative product.
How is design validation different from verification? Verification checks outputs against inputs; validation checks the device against user needs (FDA).
Is human factors testing part of design validation? Yes. Human factors validation is a core part of showing users can use the device safely and effectively.
What did FDA’s 2026 human factors guidance change? It finalized three submission categories and added a decision point on whether HF validation data must be submitted (FDA Law Blog).
When must design validation be completed? Before the device is released for use, per clause 7.3.7.
References
All pages opened and checked by October 14, 2026.
| Source | Type | Date | Used for |
|---|---|---|---|
| FDA: QMSR Design and Development (slides) | Regulator training | 2026 | Clause 7.3.7 |
| FDA: QMSR risk-based inspections (slides) | Regulator | Apr 1, 2026 | Software validation element |
| FDA Law Blog: Final HF content guidance | Law firm blog | Jun 3, 2026 | HF categories, Decision Point D |
| Emergo by UL: Final HF guidance updates | Consultancy | May 29, 2026 | Justification in lieu of data |
| FDA warning letter: Contec Medical Systems | Regulator | Oct 2, 2025 | Criteria and test plans |
| FDA warning letter: Abbott Diabetes Care | Regulator | Jan 23, 2026 | Validation of controls |