The instructions for use of a medical device are often what a user reads when something is unclear. That is why the instructions must work at exactly the moment they are needed. Instructions can be carefully written and entirely correct in content, but that does not yet tell you whether users understand them as intended. This only becomes clear when the instructions are tried out with real users.
The instructions for use are part of the device’s user interface
According to IEC 62366-1, the user interface covers all the ways in which the user and the device interact. In addition to the physical parts of the device and the software, this includes the labeling, the packaging and the instructions for use. For this reason, the instructions for use must be designed, evaluated and verified in the same usability engineering process as the rest of the user interface. They must support the safe and intended use of the device.
The MDR also requires that the information supplied by the manufacturer (including the instructions for use) is suitable for the intended users. The format, content and presentation of the information must take into account the users’ technical knowledge, experience, education and training, as well as the environment of use.
What does testing the instructions for use reveal?
The author of the instructions knows the product so well that it is hard for them to see the instructions through the eyes of a first-time user. Testing reveals things that are otherwise easily overlooked:
- sections that users cannot find or skip
- terms and expressions that are interpreted differently from what was intended
- steps where the order of the instructions does not match the user’s natural way of working
- warnings that do not attract enough attention or whose meaning remains unclear
- situations where the user makes a use error despite the instructions
These findings can also be used directly in the use-related risk analysis (ISO 14971). Use errors caused by unclear or hard-to-find instructions can be corrected before the device is placed on the market.
When should testing be done?
The best time is when a draft of the instructions for use is ready but the product is not yet final. At this stage, changes are still inexpensive and easy to make. Testing should be repeated if the instructions or the device are changed significantly, for example when a new feature is added to the software or the intended use of the device is expanded.
What does testing achieve?
- The instructions for use become clearer, and users make fewer use errors.
- The use-related risk analysis is based on observations of real users rather than assumptions alone.
- The usability engineering file contains concrete evidence that the instructions have been tested with the intended users.
How can Clinipower help?
Clinipower carries out comprehension testing of instructions for use for medical devices and health technology. We help you choose the right test tasks, recruit suitable users, conduct the testing and report the results clearly, so that they can be added directly to the usability engineering file.
