How is usability engineering applied in medical devices?

Introduction to Usability in Medical Devices

Usability research looks at the interactions between human operators and the medical device. Testing (usability in medical devices) should be conducted on anyone who plays a role in operating the device, from patients to clinicians to people responsible for sterilizing or maintaining the device. 

This topic can be tricky because medical devices are used in such a broad range of settings these days. Your device might be used in a clinical setting, such as a hospital, alongside many other devices. You might have a home-use device, which will require a potentially unskilled patient or caregiver serving as the operator of the device.

For these reasons, medical device usability testing demands a detailed analysis by engineers to understand the interactions between the device and the end user within the intended use environment. This allows you to create realistic risk acceptability models.

Human factors principles have been applied for decades to nearly every industry in which there is a high degree of risk involved with the products/services being offered. 

The medical device industry falls under that label as well, although, through human factors testing and other risk management best practices, we aim to keep that risk as low as possible.


Data from the FDA shows that up to 50% of medical device failures can be attributed to design issues, while 36% of product recalls are initiated due to design. The design of the medical device, along with its labeling, packaging and instructions for use should always promote safe and effective use by the end user.

Regulatory frameworks for usability testing

IEC 62366-1:2015 is an international standard that specifically covers the application of usability engineering to medical devices. It’s important to note that the IEC specifies that the standard covers assessment and mitigation of risk associated with normal use and use errors of the device. It doesn’t cover abnormal usage; however, it can be used to identify such risks. 

IEC 62366-1 is the overlapping standard for FDA, the European Commission, and other regulatory bodies. 

MDR does include requirements for product validation and usability-related activities, of which must be documented in a manufacturer’s technical file. Additionally, the regulation emphasizes the need to collect and evaluate usability data as part of a manufacturer’s post-market monitoring and evaluation process.

Human Factors and Usability Engineering (HF/UE) / Usability in Medical Devices

Adverse events over the past two decades have shown disturbing trends in post-market events that are attributable to design issues regarding the user interface (UI) of medical devices. Infusion pumps, automatic electronic defibrillators, ventilators, and combination products such as drug auto-injectors, have a history of use-related design problems resulting in overdoses, improper therapy delivery, incorrect diagnoses and dangerous delays in therapy. As part of the systematic process to reduce errors by regulatory bodies, medical device companies in the US and EU have been introduced to the disciplines of Human Factors and Usability Engineering (HF/UE). HF/UE has been applied in the automotive, aerospace, and telecommunications industries for more than 60 years, but has only recently been applied in the medical industry.

The term ‘usability engineering’, often used as a synonym for ‘human factors’, is also focused on creating qualities of UIs that result in rapid learning, user satisfaction, and efficient interaction.

The term ‘usability’ is a multi-dimensional quality that refers to the ability of a human to interact easily and relatively error-free with a system or product. Terms such as ‘user-friendly’ and ‘intuitive’ have emerged as descriptors of usability which translate to subjective attributes regarding whether a system or device works and acts in the way the user expects, therefore avoiding frustration and annoyance in carrying out an intention.

How did medical device regulations incorporate HF/UE into regulatory action?

Because of the rising instances of UI-induced adverse events, the US Food and Drug Administration (FDA) has begun to include HF/UE reviews as a routine part of their pre-market approval process at the Center for Devices and Radiological Health’s (CDRH) Office of Device Evaluation. This process is described in a draft guidance issued in June 2011 entitled Applying human factors and usability engineering to optimize medical device design.

Likewise, the international regulatory community has incorporated IEC 62366, Medical devices – Application of usability engineering to medical devices, as a part of the approval process outside the US. Both the FDA HF/UE guidance and IEC 62366 outline a process including activities throughout device development culminating in validation testing with the final UI design in simulated use environments.

What are the key activities in the HF/UE process and how are they aligned with the device risk assessment?

 HF/UE activities can be categorized into three major phases:

  1. Preliminary analyses;
  2. User interface design/evaluation;
  3. Simulated use testing (validation).

The relationship between the HF/UE process and ISO 14971 risk assessment flow can be summarized as:

 (a) ISO 14971 identifies an initial ‘risk assessment’ which is characterized by HF/UE preliminary analyses focused on understanding users, their use environment, tasks and risks when interacting with the device interface;

 (b) ISO 14971 calls for ‘implementing risk controls’ which is congruent with the implementation of a device UI that will limit use risks and testing of that interface for its risk control effectiveness;

 (c) ISO 14971 then requires an assessment of ‘acceptance’ of the implemented risk controls,

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