Oct 15, 2019

A new article provides step-by-step tips to help wearable injector medical device manufacturers improve design and reduce common use errors.

Wearable injectors are worn by patients to control the release of drugs subcutaneously over an extended period of time. The article addresses common characteristics that can lead to use errors, and is intended to apply to a broad range of device designs.

Reducing use errors for wearable medical devices

Quick guides for wearables are crucial due to factors such as rapid market growth and the broad spectrum of user experience levels. For example, a person with diabetes may be very comfortable administering medication, which makes it easier to adapt to a wearable injector. Conversely, people self-administering medication for the first time--perhaps to treat a rare disease--could be more prone to errors while using a wearable injector.

Authored by Cory Costantino and Lauren Fennelly, Director of User Interface Design Senior Human Factors Specialist, respectively, at Emergo by UL’s Human Factors Research & Design division, the article provides a 14-point “quick guide” that includes practical tips for design and conducting usability tests. The guide covers a broad spectrum of issues and recommendations: from providing adequate workspace for users testing a product, to button design considerations, to developing creative formats when testing products that require longer infusion times.

The new guide was published in the September 2019 edition of ONdrugDelivery.

Addressing more complex usability and design issues

“We’ve done quite a bit of work with these types of devices, and they’re becoming more and more relevant,” Costantino explains, adding that wearables include complexities that aren’t present with other, simpler forms of injection devices (e.g., auto-injectors, pre-filled syringes).

“There’s more to consider,” Costantino adds. “The devices can become more complicated due to the need for more user interactions. It has to stay with you all the time, so issues like comfort, durability, device status, start to come into play.”

Manufacturers need to consider core design principles to help users. For example, simplifying the product, a seemingly positive goal, could add unforeseen complexities, Fennelly says.

“A key issue we see with these devices is that there can be missing visibility between the user and the injector’s status,” she says. “These devices should be designed to be simple--not too many buttons or too many indicators to confuse users--but the device still needs to convey adequate feedback to users so users can know when they have or have not received their dose.”

The article helps manufacturers think through the most common use steps to incorporate a more user-centered product design.

Related human factors resources from Emergo by UL:

  • Human Factors Engineering (HFE) and usability testing support
  • Webinar: Human Factors Engineering for Combination Products


  • Andrew Micek