FDA’s Human Factors Engineering (HFE) and Usability Testing

30 Jul 2024

The area of medical device research and development known as “human factors and usability” measures and examines how people interact with medical devices to better understand their needs.

Human factors and usability engineering are tools used by medical device businesses to identify and reduce potential sources of device risk while creating safer and more functional medical equipment for end users. In order to develop a user-device interface that encourages accurate, error-free usage of the device without jeopardizing the user, human factors engineers try to understand how the intended users will interact with the equipment.

In this blog, we will discuss two principles, i.e. human factors engineering and usability testing.

By incorporating HFE and usability testing in the production of medical devices, manufacturers can easily fulfill regulatory requirements, especially the ones from FDA. In this blog, we will take a look at how manufacturers can comply with these requirements to place and market their products in the US market.

Before going into these details, let us have a look at these concepts first:

What is Human Factors Engineering (HFE)?

Human factors engineering (HFE), also otherwise known as ergonomics, is a branch of science which applies information about psychological and physical characteristics of the human body in designing devices and systems for human use. There are two major aspects of ergonomics:

• Body of Knowledge

Human factor engineering gathers data principles on human capabilities, characteristics, and limitations with regards to jobs, environments, and machines.

• Designing Process

Designing process refers to involvement of machines, work methods, environments, and systems to maintain safety, productivity, and comfort for human operators.

What is Usability Testing?

Usability testing means observing a group of representative users to determine the ease of using of a product’s design. By usability testing, manufacturers can identify any difficulties associated with using the device and problems with good usability. Usability testing can also recommend any design improvements to manufacturers. It can be conducted at any stage of the product development.

The Role of Ergonomics and Usability Testing in Designing Medical Devices

There are multiple benefits of incorporating ergonomics and usability testing while designing medical devices, such as:

• Patient Safety: Since medical devices have a direct impact on the patients’ health, it is extremely crucial for them to be free of any error. With usability testing and ergonomics, manufacturers can ensure that these devices fit neatly onto (or inside) the human body without causing any discomfort or pain.
• Regulatory compliance: Regulatory bodies require manufacturers to show the evidence of usability testing during device’s approval.
• Efficiency and productivity: A well-designed medical device will improve the workflow for healthcare providers. It will also allow their patients to have smoother interactions with these devices by considering ergonomic factors, such as comfort and visibility.
• Better market competition: Patients prefer devices that are comfortable and ergonomically sound. Thus, a manufacturer who takes care of these details can easily win their customer’s confidence.

FDA’s Guidance Document on HFE & Usability Engineering

FDA has developed a guidance document for the manufacturers so that they can easily follow the usability engineering and human factors engineering processes while manufacturing their devices. By doing so, it will be ensured that the medical devices remain safe and effective for their intended users and usage environments.

It is important to know that this guidance document (including others before it) from the FDA are not legally enforceable. They indicate the current rationale of the agency on a given topic and thus, only work as recommendations (unless otherwise specified). This can be further understood from the word “should”, which, when used, indicates a recommendation and not a requirement.

Continuing further in this blog, we will take a look at the risk management process in FDA Guidance Document.

Risk Management Process Considering HFE and UE in the FDA Guidance Document

Medical devices can incorporate design flaws that can contribute to various design-related problems. These problems have the potential to harm humans. To reduce this possibility, FDA recommends including HFE and UE in the overall risk management process.

The following are some of the most important design-related hazards included in the risk analysis:

• Mechanical hazard (impact from kinetic or potential energy from a moving object)
• Radiation hazards (non-ionizing and ionizing hazards)
• Physical hazards (injury from sharp edges and corners)
• Thermal hazards (damage from high-temperature components)
• Biological hazards (bio-incompatible and infectious agents, allergens, etc.)
• Chemical hazards (injuries from toxic substances)
• Electrical hazards (electromagnetic interface, electrical current)

Such hazards can arise from device components that are not properly configured for human interaction. Here, it is pertinent to mention a distinction, i.e. germs and pathogens, which can contaminate a device (or its components) because of use error.

Situations Causing Use-Related Hazards

Use-related hazards can be caused due to either of the following situations:

• Device is required to be used in a way that exceeds users’ physical, cognitive, and perceptual abilities.
• Device is not consistent with users’ intuition and expectations.
• The use environment of the device affects its operations such that this affect is not understood by the user.
• Device is used in a way that was not expected by the user.
• Device is used in a way that had been expected but was inappropriate
• Device is used in a way for which risk reduction or elimination methods have been applied but were not applied.

Performing a HFE/UE Analysis

It is pertinent to include HFE/UE considerations into device design, device development, and risk management processes. The following three steps should be followed for a successful HFE/UE analysis:

• Step 1: Identification of the anticipated use-related hazards and unanticipated use-related hazards through preliminary evaluation.
• Step 2: Development and application of measures that eliminate or reduce use-related hazards that could otherwise cause harm to the user.
• Step 3: Demonstrate if the final UI is safe and effective. This would be done by conducting human factors validation testing.

Need HFE/UE Consultancy?

If you are a medical device manufacturer who is specifically looking forward to learn more about fulfilling HFE/UE requirements of US FDA, then our regulatory consultants at TS Quality and Engineering can provide all the help. We will help you comply with not only HFE/UE requirements, but will also work to plan a robust risk management framework for your organization. Inquire through our website tsquality.ch and get your consultation session booked today!