Table 2.

Interviews and focus groups guidelines.

Steps	Duration (Min)	Purposes
Introduction	5 min	✓Presentation of the main objective for the interview/focus group.
Discussion	30 min	✓Discussion on the main advantages and limitations of the new double-chamber syringe, comparing them with the standard syringes (“We would like you to summarize your experience with this new medical device, the Duo Syringe. We want you to help us to identify its advantages and potential, as well as any limitations or difficulties that you have identified when using it in these usability tests”). ✓The participants are also asked to answer the usability questionnaire.
Conclusion	5 min	✓Show appreciation for participation and obtain main (anonymous) information to characterize the group.