Table 1.
Summary of characteristics of calprotectin home tests and companion ELISAs.
Fig 1.
We used 40 stool samples that covered the whole range of potential calprotectin values and performed 1440 smartphone readings and 120 ELISA measurements.
Table 2.
Agreement of results between three different home test and corresponding ELISA using Bland-Altman plot analysis.
Fig 2.
Bland-Altman plots showing difference against mean for (A) IBDoc vs. fCAL; (B) QuantOn Cal vs. IDK Calprotectin; and (C) CalproSmart vs. Calprotectin (ALP).
The grey zone corresponds with the predefined acceptable limits of difference, which were arbitrary set at ±100 μg/g for the lower range and at ±200 μg/g for the higher range.[7] The dotted line is the bias (mean of the differences), the dashed lines are the upper and lower 95% limits of agreement (LOA).
Fig 3.
Histogram of differences in calprotectin concentrations (μg/g) for (A) IBDoc minus fCAL; (B) QuantOn Cal minus IDK Calprotectin; and (C) CalproSmart minus Calprotectin (ALP).
Fig 4.
Simplified concordance matrices showing calprotectin readings with (A) IBDoc against fCAL; (B) QuantOn Cal against IDK Calprotectin; and (C) CalproSmart against Calprotectin (ALP).
Fig 5.
Reading error rate per home test for different smartphone types.
Fig 6.
Student’s mean system usability scale (SUS) scores on day 1, 7 and day 10 of testing.
SUS scores above 90 should be converted to “A”; 80–90 to “B”; 70–80 to “C”; 60–70 to “D”; and below 60 to “F”.