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Mar 29, 2022

Successful prototyping for medical devices

Those who use prototyping at an early stage in the development of medical devices not only fulfill the formative evaluation required by DIN EN 62366. Prototyping helps you avoid cost-intensive corrections and optimally aligns the usability and operating safety of your product with your target groups. When is prototyping ideally used in the medical field? What are the different prototyping methods? What in particular should you consider when prototyping for medical devices? You learn more in our article.

What is a prototype?

A prototype is a simplified, but often already functional model of a planned product or service. With prototypes, product concepts can be tested quickly and cost-effectively. This way, you can check the usability and operating safety of your medical products early on in development and use the feedback gained to iteratively further develop and optimize your product.

What are the benefits of prototyping?

Medical prototyping helps to optimally align the product concept step by step to the requirements in the medical environment. This makes the operation of your products more efficient and safer. At the same time, you reduce the risk of bad investments by using prototyping.

Safe operation

Especially in the demanding development environment of medical technology, we recommend using prototyping for product and service development. Because in medical technology, operating errors typically have serious and sometimes life-threatening consequences. In product design, many different requirements must be considered due to the special context of use: Laypersons (for example, family caregivers or patients themselves) and trained professionals often operate medical applications.

In our project with the test experts from QIAGEN (meanwhile DIALUNOX), both the context of use and the target groups were very heterogeneous. QIAGEN's rapid test reader can be used to test liquids for different properties – for example, by a lab technician in the laboratory, but also by a police officer on patrol. This required a stringent operating concept that also guides users without medical knowledge safely and efficiently through the test process.

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Efficient interaction

The use of medical devices often takes place in critical situations under time pressure. The locations where medical technology is used in the operating room or intensive care unit also entail special requirements in terms of lighting conditions or background noise. In our HoloMed project, an augmented reality application was developed to support surgeons during brain operations. To test the results, we prototyped in a hackathon with the entire team of usability experts, designers, and developers. This allowed us to quickly see what worked and what didn't, and to try out the application ourselves. Together with our partners, we developed a functional prototype.

We checked whether this prototype meets the high requirements of the medical environment in two test loops under real conditions in the operating room: Are the steps clearly presented for neurosurgeons to understand? Are the AR application holograms easy to see in the bright light of an operating room? Do the holograms cross-fade other devices? Are the holograms placed sensibly so that an ergonomic posture of the user is ensured? Is the application clear and at the same time unobtrusive enough that the focus on the patient is not lost? Using the insights from the tests, concepts and designs were developed that integrate perfectly into existing workflows and doctors' mental models, making neurosurgical operations safer and more efficient.

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Medical device development with prototyping

Medical prototyping is an essential part, especially in the early stages of innovation and product development:

  • Ideation: In this phase, prototypes help to visualize ideas and make them tangible. In medical technology, user groups are very narrowly defined by purpose and solutions must fit very precisely into existing clinical processes. This makes it all the more important to fully understand the problem space and gain quick insights into the feasibility or viability of product ideas.
  • Design: Prototypes support you in making ideas, concepts and design tangible and in developing them further. In most cases, the prototypes in this phase already represent the basic idea of the user interface, which is constantly developed further
  • Iterative testing: Target groups evaluate the designed solutions based on the prototypes. Your feedback contributes to the ongoing improvements of your prototype with increasing degree of detail (fidelity). DIN EN 62366 and FDA also require formative evaluation of medical technology during development, ideally with representative users. Validation of usability with medical prototyping is the gold standard for this requirement and must be included in the documentation (usability engineering file) accordingly.

The summative evaluation, on the other hand, is normally carried out with the final product.

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Prototyping methods

  • Click dummy: For our medical clients' interaction and design testing, we create digital interactive prototypes in tools such as Figma, Axure, or Adobe XD. Users process typical tasks with it and thus interact directly with the product concept. Based on the feedback, designers then easily adjust the concepts and design.
  • Haptic prototypes are suitable for being able to check product handling and form factor: Does the insulin pen fit perfectly in the patient’s hand? Can users cope with the tablet dispenser despite motor impairments due to their illness? Is the fixed heat radiator easy to read and operate? Thanks to manufacturing using additive manufacturing, haptic prototypes can be implemented quickly and cost-effectively.
  • Natural language interfaces can be experienced with Wizard of Oz prototypes, for example. In this process, the test coordinator or moderator simulates the system responses, in this case the voice output.
  • Role plays are also very suitable for testing services. Through role plays, the observing participants gain a realistic insight into the user experience of a service.

Low fidelity vs. high fidelity

Prototypes differ in their degree of detail and realism. The so-called “fidelity” influences the visual design, interactivity and content of the prototypes. The following applies: The less energy has been used in production, the easier it is (also from a psychological point of view) to discard ideas.

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Low-fidelity prototypes

  • Use in early development phases
  • Tests whether product idea or concept meets requirements
  • Low degree of realism
  • Visual design does not correspond to the later design of the product.
  • Interactivity is limited or has to be imitated or explained by the test administration (e.g., Wizard of Oz method)
  • Examples: Paper prototypes, simple HTML click dummies or digital wireframes

High-fidelity prototypes

  • Use in later development phases
  • Suitable for testing concept and design under realistic conditions
  • Focus is on detail issues such as design and animations
  • Functional prototypes
  • Visual design close to the later product design
  • Users can use it to perform previously defined tasks independently.
  • Interactivity is given for the previously defined tasks.
  • Content consists of realistic data and text.
  • If the high-fidelity studies reveal little or no need for revision, these tests form an ideal basis for the summative evaluation in the context of the Usability Engineering File (UEF).

6 tips for medical prototyping

  • Realistic data: The accuracy of the exemplary content (e.g., texts, diagnoses, vital signs, recordings) is particularly important for medical target groups (physicians, pharmacists, medical professionals). If the medical prototype contains content errors, they often find it difficult to focus on the “design feedback”. “Lorem Ipsum” should also be avoided if possible.
  • Operating safety: The validation of usability focuses on safety in handling the product. DIN EN 62366 requires that all specified usage scenarios are evaluated in terms of safety. Therefore, regular coordination with risk management before and after testing is particularly important.
  • Experience in moderation: Experienced user research moderators are especially important in the medical context. They ensure that the legal requirements are met. It takes a lot of expertise to extract the maximum amount of knowledge from the studies with users to optimize your products based on this.
  • Precise task definition: Especially in the medical context, a well formulated task is fundamentally important. A good task is formulated so precisely that it does not provoke any queries, but at the same time does not anticipate a solution path (e.g., by naming terms that can be seen directly in the display). It should also be based on a realistic usage scenario.
  • Realistic test setting: Many medical devices will be used together with other products, especially in hospitals. I.e., many devices compete for the attention of users. This mainly concerns the alarm management of the respective devices: how do I avoid false alarms and alarms that are irrelevant for the staff? How do I communicate the proper urgency of my alarms to avoid staff stress and patient and family panic? This must also be considered in the study design.
  • UEF documentation: You should document all tested prototype states individually or collectively in the evaluation report. The more uniform and structured, the better the notified bodies can understand your evaluation concept. Appropriate templates help to save time and not to forget anything.


Medical prototyping makes a significant contribution to identifying challenges before and during the development of products and services. You can gather valuable insights to optimize concept and design. Using prototypes, you test the functionality and usability of your medical product already during development – before you start with the implementation. In this way, you ensure that products and services are created that provide users with the best possible support in their context of use. You avoid time-consuming and cost-intensive corrections and make the development of your products faster and more effective. Those who invest money and time in medical prototyping at the beginning ultimately save money and time.

The authors

Dominik Zenth has been developing user-friendly and creative solutions at UID since 2015. Companies from the medical and pharmaceutical sectors in particular benefit from the knowledge of the trained health scientist and physiotherapist. As a specialist in user research and design of health applications, he understands the needs of users and translates them into intuitively usable products.

Whether content or offer creation – Silja Donadel networks marketing and sales at UID. The literature and linguistics expert is always on the lookout for exciting topics from the UX world that will inspire our customers.