JMIR Publications

ABSTRACT

Background:

Cancer patients undergoing cytotoxic chemotherapy face an elevated risk of developing serious infection as a consequence of their treatment, which lowers their white blood cell (WBC) count and, more specifically, their absolute neutrophil count (ANC). This condition is known as neutropenia. Neutropenia accompanied by a fever is referred to as febrile neutropenia (FN), a common side effect of chemotherapy with a high mortality rate. Timely detection of severe neutropenia (ANC < 500/μL) is critical in detecting and managing FN. Current methods rely on blood draws, which limit them to clinical settings and do not allow frequent or portable monitoring. In this study, we demonstrate the usability of PointCheck™, a non-invasive device for neutropenia screening, in a simulated home environment without clinical supervision. PointCheck™ automatically performs microscopy through the skin of the finger to image the blood flowing through superficial microcapillaries, and enables remote monitoring of neutropenia status, without requiring venipuncture.

Objective:

This study aims to evaluate the usability of PointCheck™, a non-invasive optical technology for screening severe neutropenia, with the goal of identifying potential User Interface (UI), functionality, and design issues from the perspective of untrained users.

Methods:

We conducted a multi-center study using quantitative and qualitative approaches to evaluate the usability of PointCheck™ across N=154 untrained participants. We used a mixed-method approach to gather usability data through user testing observations, a short-answer qualitative questionnaire, and a standardized quantitative System Usability Scale (SUS) survey to assess user experience and satisfaction.

Results:

We found that N=108 (70.1%) of participants scored above 80.8 on the SUS across all sites, with a mean SUS score of 86.1 across all sites. Furthermore, the SUS results indicated that N=145 (96.0%) of users who completed the SUS survey found they learned how to use PointCheck™ very quickly, and N= 141 (93.0%) felt very confident using the device.

Conclusions:

We have shown that PointCheck™, a novel technology for non-invasive, home-based neutropenia detection, can be safely and effectively operated by first-time users. In a simulated home environment, these users found it easy to use, with a mean SUS score of 86.1, indicating excellent perception of user experience and placing this device within the top 10th percentile of systems evaluated for usability by the SUS. Clinical Trial: ClinicalTrials.gov: H12O: NCT04448314 https://clinicaltrials.gov/ct2/show/NCT04448314 BMC: NCT04448301 https://clinicaltrials.gov/ct2/show/NCT04448301