5 Considerations for Human Factors Testing

Often, when we hear about medical device recalls or failures, the first instinct is to blame the manufacturer or assume a mechanical error. However, problems with medical devices aren’t always in the device itself. In some cases, the device is simply difficult or complicated to use, leading to human error that causes problems.
 
Because the human factor cannot be ignored when it comes to medical device testing, the FDA recently released a draft list of devices that require human factors testing as part of the approval process before the device can be released to market. The devices on the list were chosen because they are the most likely to cause serious harm should there be a user error, and included everything from anesthesia and dialysis machines to infusion pumps (both external and implanted), home-use negative pressure wound therapy devices, and robotic surgery devices. The FDA also requires that any device manufacturer submitting devices that are not on the list, but that may have serious adverse effects due to human error, must also submit human factors testing results as part of their application for approval.
 
For manufacturers of medical devices, there are a number of considerations to keep in mind when conducting human factors testing. When planning human factors testing for a device, manufacturers cannot forget to consider the following five points.
 
1. Consider Both Provider and Patient Usage Needs
Anyone using a medical device should be able to do so without making errors that could compromise the safety of the device. This includes both providers and patients, when appropriate. Some of the factors that need to be considered are the overall state of health of the user, the physical strength and stamina of the user, the required dexterity or coordination to use the device, the ability to follow instructions (and in some cases, the cognitive function and memory of the user), and the ability to learn how to use the device. All of these questions will not apply in every situation, but it’s important to consider who will be using the device and testing for usability in a variety of scenarios and among a variety of different users.
 
2. Testing Is for Usage Purposes, Not Marketing
One common issue in usability testing is that the test designers move away from the purpose of the test. However, tests for marketing purposes generally involve focus groups or other users and involve prototypes and research centered around how much the users like the product and their likelihood of using it. These tests do not explore the actual usability of the product in a tightly controlled, scientific environment. Even if the marketing test groups indicate they like a product or think it is easy to use, that doesn’t meet the usability requirements of the FDA. Human factors testing looks at how a user actually uses a device in an environment that mimics actual use, and gauges the performance in terms of the likelihood of an error or difficulty in use.
 
3. Conduct Both Formative and Summative Testing
Formative testing puts the device in your users’ hands in the prototype stage. It’s an important part of biomedical device development, when you determine which technical specification needs to be implemented or adjusted; for example, your orthopedic device may need more memory on the microchip and a UNI/O Serial EEPROMs is in order to ensure it can carry out every task sufficiently. However, you also need to conduct summative testing, which validates the human factors testing. This testing occurs after production, and includes the training and labeling of the final device. It’s vitally important to include both types of testing—in fact, it’s exactly what the FDA is calling for.
 
4. Test Both Instructions and the Device  
In addition to testing the device for usability, human factors testing requires testing the instructions to determine if there are any issues that could potentially cause confusion or error. Asking users to test the devices according the exact instructions can reveal problems that might not otherwise appear. Ideally, the instructions for use testing should be conducted early on during the formative testing to identify problems as soon as possible.
 
5. Testing Should Be Ongoing
Human factors testing is an ongoing process. Even after the device is released to market, manufacturers and designers should be gathering feedback and test results to determine whether any changes or adjustments are necessary for future iterations of the product.
 
Human factors testing is a vital part of developing a safe, useful medical device. Working with a human factors engineer will allow you to create products that do not pose a risk to users, while also speeding the process of FDA approvals. By keeping these points in mind, you will save time and money, and create better products.