P599 Home testing for faecal calprotectin: follow-up results from the first UK trial
Raker J., Ford C., Pavlidis P., Medcalf L., Choong L.M., Chung-Faye G., Dubois P., Hayee B.
King's College Hospital NHS Foundation Trust, Department of Gastroenterology, London, United Kingdom
Faecal calprotectin (FCAL) is a useful test for monitoring of inflammatory bowel disease (IBD) activity. However, providing a stool sample in person to the hospital laboratory is anecdotally unpopular. A new FCAL kit (IBDoc™, Bühlmann) enables self-testing using a proprietary collection tube, camera smartphone and app. The aims of this study were to assess patients' adherence to and experience of using IBDoc™; to compare the assay to the standard laboratory test; and to determine if IBDoc™ can be used to predict a flare of disease within a four month period.
After focussed training, participants were asked to use IBDoc™ once a month for four months and provide a standard stool sample to be tested with standard ELISA (Bühlmann). The following questionnaires were applied before and after testing: GAD-7 (anxiety), PHQ-9 (depression), IBD-control-8, Multi-dimensional Health Locus of control (MHLC) and Cognitive Behavioural Responses to Symptoms (CBSRQ). Patients were also asked to record their experiences and preferences for testing on a proprietary questionnaire. Electronic patient records and endoscopy and histopathology reports were retrospectively reviewed for patients who had FCAL results by both methods at one time point. A faecal calprotectin of >100 μg/g was defined as a positive result.
Overall, 54 patients (Crohn's: 23, UC: 31, mean age 36.0) were enrolled. Participants completed a median of 3 tests during the study with 19/54 (35%) completing all four set time points and 17/54 (32%) returning no samples. There was no difference in any of the questionnaire scores between compliant and non-compliant patients. Overall, 85% of respondents stated a preference for IBDoc™ of which 74% would want this to be in the context of prompt contact from the hospital team in the event of a positive result. There was moderate correlation of FCAL results between the two methods (r=0.77, p<0.0001). At least one paired laboratory FCAL and IBDoc™ result was available for 37 patients, of which 30 were in remission at the time of the test. To predict a flare within four months, the IBDoc™ FCAL had a sensitivity of 89%, specificity of 33% and NPV of 87.5%, compared with 78%, 57% and 86% respectively for the laboratory test.
There was reasonable uptake and adherence to a demanding testing regimen with 85% of respondents preferring the IBDoc™ test over other methods. The home testing kit results show only moderate correlation to laboratory results. A negative FCAL (<100 μg/g) by either method is a useful test to exclude a flare within four months, but positive results should be interpreted with caution and repeat testing would be advisable prior to treatment escalation.