Capillary Blood Self-Sampling for Therapeutic Drug Monitoring: A Mixed-Methods Usability Study of the True Dose^® Kit

Area of Science:

• Medical Device Usability Engineering
• Human Factors in Healthcare
• Diagnostic Self-Sampling Technologies

Background:

• Usability is critical for medical device safety and effectiveness, particularly for self-sampling kits.
• The True Dose kit aims to facilitate capillary blood self-sampling, requiring rigorous usability evaluation.
• Adherence to EN 62366 standards is essential for medical device usability validation.

Purpose of the Study:

• To evaluate the usability of the True Dose kit for capillary blood self-sampling according to EN 62366.
• To assess user performance, experience, and confidence with the True Dose kit.
• To identify areas for improvement in the True Dose kit's design and instructions.

Main Methods:

• A convergent parallel mixed-methods design integrating quantitative and qualitative data.
• Twenty-five participants performed capillary blood self-sampling using the True Dose kit.
• Quantitative metrics (blood volume, air bubbles, duration) and qualitative data (interviews, feedback) were collected, alongside System Usability Scale (SUS) and Test Feedback Questionnaire (TFQ) scores.

Main Results:

• The True Dose kit achieved a high overall SUS score of 82.70, indicating good usability.
• 92% of participants successfully collected adequate blood samples, with a median sampling time of 10.42 minutes.
• Participants reported challenges with instruction clarity and managing stress during blood flow, suggesting a need for enhanced visual guidance and feedback.

Conclusions:

• The True Dose kit demonstrates significant usability potential for capillary blood self-sampling.
• Improvements in instructional design and stress management strategies are recommended to optimize user experience.
• Further refinement can enhance consistent performance and user confidence in self-sampling procedures.