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Validate Smarter, Not Harder: Exploring the Scope of Critical Tasks in an HF Validation Test

Discover efficient approaches to streamline HF validation testing for medical devices. Learn about alternative methods, regulatory insights and best practices from Emergo by UL.

human factors validation on computer screen

June 21, 2024

By Stephanie Larsen 

Many of you have probably had the experience of writing an HF validation protocol, running an HF validation test, or writing an HF validation report, where you encounter a finding that just “feels” out-of-scope or inefficient to collect. Traditionally, we accept the FDA’s expectation of evaluating every critical task, and we of course find HF validation testing to be an essential activity. But is there a way we might be able to streamline this process? Based on our HF validation testing experience, as well as FDA’s review of a couple streamlined protocols for clinical use products, we think that there is. 

When assessing future HF validation tests for streamlining opportunities, some elements that we look for include: 

  • Whether the intended users are trained professionals who have credentials and formal experience performing the given tasks 

  • Whether you have access to existing human factors data from a similar product that might be relevant  

  • Whether the product format is well-established on the market 

On the other hand, some elements that might be considered a “no go” for this approach are: 

  • If the product is novel or complex without a track record of usability performance 

  • If this is a manufacturer’s first product they’re submitting for FDA approval with no past data to lean on  

  • If the product’s users are laypeople with high variance in backgrounds, experience, and other performance-shaping factors 

Below, we share some brief case studies illustrating a proposed streamlined approach to HF validation testing. Noting the nuances of critical tasks in an HF validation test, these case studies are meant to provoke thought rather than provide concrete guidance on how to plan your HF validation test.  

Case study A – Existing HF data from similar products 

Wrist blood pressure monitor 


Manufacturer development history 
Previously developed an arm blood pressure monitor that is currently on the market 

Streamlining opportunities 
The cleaning steps and some error messages of the wrist blood pressure monitor are identical to the arm blood pressure monitor in terms of process and the related IFU design; therefore, there is applicable data from the previous HF validation test. As such, the related critical tasks could potentially be considered out-of-scope.  

Case study B – Common contraindications 

Urinary catheter with a new insertion tip and insertion mechanism  

Registered nurses 

Manufacturer development history 
Has not previously developed a urinary catheter 

Streamlining opportunities 
Registered nurses in hospital environments frequently use urinary catheters and are likely familiar with common cautions and contraindications based on their training and experience. Critical tasks related to cautions and contraindications that are considered standard of care (i.e., not product-specific) could potentially be considered out of scope.  

Case study C – Common product type 

Pen injector 

Physicians and registered nurses 

Manufacturer development history 
Previously developed other pen injectors for different medications 

Streamlining opportunities 

Consider omitting critical tasks that are consistently standard across all injection devices, like preparation tasks (e.g., cleaning the injection site, device inspection) because these tasks are known by clinicians based on their training and experience. This exclusion might be particularly justifiable if the manufacturer has a track record of evaluating these tasks with other pen injectors, and the IFU structure and steps for preparation are the same between products.  

Omitting some critical tasks in your HF validation test will have implications for your protocol, data collection, and reporting. In your protocol, make sure to clearly define what is in-scope and out-of-scope, as well as which critical tasks fit into each category. When collecting HF validation test data, consider how confident you are in your streamlined approach, and use your level of confidence to guide how much data you collect on out-of-scope critical tasks that inherently appear in your use scenario workflows. For example, if you’re highly confident in your streamlined approach, you might collect no data on out-of-scope critical tasks. Lastly, for reporting, you would not document data related to out-of-scope critical tasks in the formal report, but you could consider documenting that data in a separate concise memo if it might be useful for future considerations.  

By considering opportunities to streamline your HF validation test, your team could save time, effort, and money. Ensure you carefully consider if this approach could be appropriate and pre-submit your protocol to FDA prior to conducting your test to get their input on your planned approach.  

Contact our team to learn more about streamlining your HF validation efforts.  

Stephanie Larsen is a Managing Human Factors Specialist at Emergo by UL.   


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