Aug 04, 2022

Medical Device & IVD Usability Testing and FDA Human Factors Requirements

The technology behind your device may be brilliant, but sales will suffer if your user interface and/or ergonomics are subpar. Worse yet, you open your company and patients/users to risks that might have been avoided with proper device usability testing.

FDA has long placed an emphasis on usability testing, which they refer to as human factors. In recent years, the European Union has also placed far more emphasis on risk management, an important facet of which is how the user interfaces with the device.

Why Do We Need to Do Device Usability Testing?

Sure, your design team may be awesome, but there are two primary reasons you need to do usability testing: (1) It’s required in the US and Europe, and (2) you have an ethical and legal responsibility to make sure your device is safe. The usability analysis work you conduct will be part of your risk management file. Not sure where to get started? There are two essential documents you’ll want in your toolbelt:

  • IEC 62366-1:2015/AMD 1:2020 – Medical devices – Part 1: Application of usability engineering to medical devices – Amendment 1 This international standard specifies a process for manufacturers to address usability in medical devices.
  • US FDA Guidance – Applying Human Factors and Usability Engineering to Medical Devices

These two documents will help you apply the customer requirements found in section 820.30 of the FDA Quality System Regulation, as well as clauses within ISO 13485:2016, including:

  • Clause 5.2, which states that usability is a customer requirement.
  • Clause 7.1, which says that the stated intended use and any reasonably foreseeable misuse – and indications for use – should be documented in the design and should also be included in risk management activities.
  • Clause 7.2, which states that you should determine any user training needed to ensure specified performance and safe use of the medical device.

Although IEC 62366-1 is barely mentioned in ISO 13485:2016, when the next version comes out it is expected that usability will be emphasized far more.

What’s the difference between usability testing, usability engineering, and human factors?

  • Usability engineering focuses on the interaction between users, devices, and the use environment.
  • Usability testing discovers the potential for user errors so they can be addressed.
  • Human factors help reduce medical errors and, therefore, harm to patients.

FDA Human Factors Engineering

As mentioned earlier, the FDA guidance on human factors is the primary guide you will use to meet FDA design control requirements outlined in FDA QSR 820.30. Those requirements tell you, for example, what needs to be done with regard to design validation [820.30(g)], but not how to do it. That’s where the FDA guidance comes into play. Your ultimate goal is to produce a human factors engineering/user experience (HFE/UE) report following the outline below. (You’ll find a detailed description of what should be included in these sections on pages 32 through 34 of the guidance.)

  1. Conclusion and summary of processes and results to support a conclusion that the device is safe
  2. Description of intended device users, uses, use environments, and training
  3. Description of the device user interface
  4. Summary of known use problems
  5. Analysis of hazards and risks associated with the device
  6. Summary of preliminary analysis and evaluations
  7. Description and categorization of critical tasks
  8. Details of human factors validation testing

During this process you will profile your typical device users (physical size, cognitive abilities, language skills, etc.); device use environment (lighting, noise, clutter in the room, etc.); and the device user interface (size/shape of device, indicator lights, graphical user interface, etc.).

This guidance should be used in conjunction with IEC 62366-1, which is a consensus standard recognized by FDA.

European Usability Requirements

The word usability may only be mentioned twice in the entire MDR, but that doesn’t mean it’s not an important factor in risk management compliance. Again, even though IEC 62366-1 is not yet a harmonized standard under the MDR or IVDR, it eventually will be and you are advised to follow it for MDR/IVDR compliance, just as you would for FDA compliance. In the MDR, Annex I contains several references highlighting the need for manufacturers to take medical device usability seriously. They include:

  • Annex I, Chapter 1, Section 5: “In eliminating or reducing risks related to use error, the manufacturer shall reduce as far as possible the risks related to the ergonomic features of the device and the environment in which the device is intended to be used (design for patient safety), and give consideration to the technical knowledge, experience, education, training and use environment, where applicable, and the medical and physical conditions of intended users (design for lay, professional, disabled or other users).
  • Annex I, Chapter 1, Section 14.2a: “Devices shall be designed and manufactured in such a way as to remove or reduce as far as possible the risk of injury, in connection with their physical features, including the volume/pressure ratio, dimensional and where appropriate ergonomic features.”
  • Annex I, Chapter 1, Section 14.6: “Any measurement, monitoring or display scale shall be designed and manufactured in line with ergonomic principles, taking account of the intended purpose, users and the environmental conditions in which the devices are intended to be used.”

Similar clauses can be found throughout the IVDR by searching for the word ergonomic.

The Importance of Examining “Reasonably Foreseeable Misuse”

An important component of risk management and human factors engineering involves looking at “reasonably foreseeable misuse” by users of your device. Potential misuse can range from simple confusion to intentional circumvention of instructions. Either way, you need to seriously consider all misuses that may present a hazard to users or patients.

Reasonably foreseeable misuse falls outside the scope of IEC 62366-1 but is within the scope of ISO 14971:2019. Here’s a practical example taken from ISO/TR 24971, the technical standard used to apply ISO 14971:

“A single-use medical device is designed to be used only once, but it is reasonably foreseeable that some users might attempt to reuse the medical device. Therefore, warnings against reuse and indications of the possible harm resulting from reuse were included in the accompanying documentation. Application of usability engineering according to IEC 62366-1 demonstrated that this information for safety would be effective, i.e. users would know the correct use and understand the risk of reusing the medical device. However, the usability evaluation also showed that some users are likely to disregard this information and intentionally reuse the medical device. Intentional reuse can be considered abnormal use, which is beyond the scope of the usability engineering process, because the associated risks cannot be controlled in the user interface (see 3.1 and 3.26 of IEC 62366-1:2015). Since this behaviour can be considered reasonably foreseeable misuse, the risks from such reuse need to be analysed in the risk management process and evaluated against the criteria for risk acceptability according to ISO 14971:2019. It could be necessary to implement risk control measures outside the user interface.”

Usability Testing Is a Postmarket Activity Too!

You might think that because usability testing is required, relatively few issues arise related to usability. Au contraire! These issues pop up daily and are far more common than most people realize. If you search the FDA MAUDE database, select the product problem drop-down entitled “human-device interface problem,” and adjust the dates to include the three-month period April 1, 2022 through June 30, 2022, you will find hundreds of reported cases.

Usability challenges are legitimate complaints and need to be addressed in the complaint-handling process. Your postmarket surveillance plan (PMS) should capture all safety and performance data related to usability. Article 83(f) of the MDR says: “Data gathered by the manufacturer’s post-market surveillance system shall in particular be used or the identification of options to improve the usability, performance and safety of the device.”

Want to Learn More?

There is so much more to know about usability testing. If you are interested in learning more about this topic, consider our intensive class entitled Usability Principles for Medical Devices: Interpreting and Implementing IEC 62366. The course explores FDA and EU requirements, plus covers all aspects of the standard. You’ll walk away with a solid understanding of how to execute usability testing for your product portfolio.

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