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P452 Usability study of a smartphone-based patient monitoring system measuring Calprotectin for therapy follow-up

C. Reinhard*1, J. Weber2, C. Niederberger1, F. Perretta3

1BÜHLMANN Laboratories AG, Operations, Schoenenbuch, Switzerland, 2BÜHLMANN Laboratories AG, R&D, Schoenenbuch, Switzerland, 3BÜHLMANN Laboratories AG, QA, Schoenenbuch, Switzerland


Inflammatory Bowel Disease (IBD) is a chronic inflammation of the gut presenting with phases of active inflammation, remission and relapses. IBD treatment goals are mucosal healing and persistent remission. Calprotectin measured in patients' stool samples is a well-established biomarker to measure the inflammatory activity in the gut. Periodical assessment of calprotectin levels is important to measure effectiveness of the treatment as well as predicting relapses. Until now affected patients send in their stool sample for laboratory analysis, leading to long time spans between sample collection and final test result. To ensure real-time information about the inflammatory activities in the gut for both, the clinician and the patient, we have developed a calprotectin home test, called IBDoc®. The IBDoc® consists of a stool extraction device (CALEX® Valve) and an immunochromatographic rapid test, which is measured using a smartphone App (CalApp®) controlling the phone's camera. Once the test is measured the result is sent to a webserver (IBDoc® Portal) allowing the treating physician immediate access to the result.

The objective of this study was to evaluate the usability of the IBDoc® calprotectin home test system with lay users in respect of handling both, the physical test components as well as the integrated software.


25 voluntary healthy lay users (age 24-60 years) naïve to the IBDoc® system were trained to perform the test and asked to carry out a calprotectin stool test by themselves at home. The lay users then filled in a questionnaire based on 5-point Likert scale questions, free commentary sections and system usability scale (SUS). The SUS is commonly used in measuring and comparing the usability of integrated software systems.


All 25 lay users were able to generate a calprotectin test result by themselves. 24 out of 25 users were able to collect and extract a stool sample with the CALEX® Valve device without major problems, and 22/25 were confident that the rapid test was performed correctly. When asked how easy it was to measure the test cassette with the smartphone, the users judged this question with an average score of 4.4 on a 5-point Likert scale. 21/25 users felt comfortable to use a smartphone for a medical test. The IBDoc® system reached a mean SUS score of 82 on a scale from 0 to 100. This SUS is well above the software industry's average of 681.


This study shows that calprotectin home testing using a smartphone as measuring system was well accepted among the tested lay users. The complexity of the application is low, the entire IBDoc® system can be considered very user-friendly and is easy to handle by lay users without prior knowledge or experience of immunochromatographic rapid tests.


[1] Brooke, (2013), SUS: A Retrospective, J Usability Studies, 29-40