P341 Analytical performance of a new iPhone-based patient monitoring system comparable to ELISA for measuring faecal calprotectin in inflammatory bowel disease patients
K. F. Wintgens*1, A. A. Wulandari2, A. Dignass3, 4, F. Hartmann3, 4, J. Stein2, 3
1Immundiagnostik AG, Bensheim, Germany, 2DGD Clinics Sachsenhausen, Frankfurt/Main, Germany, 3Interdisciplinary Crohn Colitis Centre Rhein-Main, Frankfurt/Main, Germany, 4Agaplesion Markus Krankenhaus, Frankfurt/Main, Germany
Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory disorder presenting with phases of active inflammation, remission, and relapse. Faecal calprotectin (fcalpro) measurement has become established for the monitoring of inflammation activity. Periodical assessment of fcalpro levels has been demonstrated to be an important non-invasive indicator of treatment efficacy and predictor of relapse. However, until now, fcalpro determination required patients to send stool samples in for laboratory analysis, resulting in a long delay between sample collection and final test results. We developed a simple home-based calprotectin test system called QuantOnCal to allow patients to regularly monitor their own inflammatory status by testing fcalpro levels in the comfort of their own home.
QuantOnCal consists of a stool extraction device (IDK® Extract) and an immunochromatographic rapid test performed by an iPhone App via the phone camera. Results are automatically sent to a webserver (QuantOnCal website), where they are displayed for monitoring by the consulting physician or IBD nurse. The objective of this study was to validate the QuantOnCal test system by comparing its quantitative performance with a standard ELISA-based method. Stool samples from 157 IBD and non-IBD patients containing various levels of calprotectin (95 IBD ulcerative colitis [UC]/Crohn’s disease [CD]/active/remission, 42/43/48/47; 33 irritable bowel syndrome (IBS) 23, carbohydrate malabsorption [Chm] 6, and diverticulitis [Div]) were either loaded onto immunochromatographic test cassettes or analysed with a commercial ELISA test (Immundiagnostik, Bensheim, Germany). The QuantOnCal app was installed on 4 different iPhone models (iPhones 4, 4s, 5c, 6). Agreement between QuantOnCal testing vs ELISA was assessed by Analyse-it for Microsoft Excel.
The QuantOnCal system produces a quantitative test result between 25–2000 mg/g fcalpro/g of stool, covering the clinically relevant range of this biomarker. The total agreement (TA) was 94.6% with 0% false positive and 0% false negative rates. The TA for fcalpro between the 4 different iPhone models was 91.3%.
QuantOnCal is a new, complete and validated test system which allows the IBD patient to monitor and follow his inflammatory status by measuring the IBD biomarker, faecal calprotectin, using his/her own smartphone. The performance of the QuantOnCal test system was shown to be comparable to the professional, ELISA-based method.