EXPRESS: Use of faecal immunochemical testing as an alternative to faecal calprotectin in children.

Sandhu, Kirn; Naik, Sandhia; Ayling, Ruth M

BACKGROUND Faecal calprotectin (FCP) has been widely used as a non-invasive marker of intestinal inflammation in children. Measurement of faecal haemoglobin (f-Hb) using faecal immunochemical test (FIT) is well established in adults for detection of colorectal cancer. In adults, f-Hb has been recommended as a reliable tool to aid identification of those at low risk of significant bowel disease and has also been used in inflammatory bowel disease to assess mucosal healing. AIMS We aimed to evaluate the performance of f-Hb in the paediatric population and compare it with FCP. METHODS Children being assessed in the paediatric gastroenterology clinic for bowel symptoms had a sample sent for both FCP and f-Hb. Samples were collected over a 10-month period from November 2018 to September 2019. f-Hb was measured using an OC-Sensor. FCP was measured using LiasonïCalprotectin. RESULTS 143 samples were returned for f-Hb and in 107 a paired FCP was also available. f-Hb correlated with FCP, Spearmanâs rank coefficient 0.656 (p<0.0001). There were 35 patients with f-Hb >20 µg/g and in 32 of these patients FCP was >200 µg/g. 74 patients with f-Hb and 38 patients with FCP underwent colonoscopy. Patients with normal histology had f-Hb <4 µg/g; f-Hb >20 µg/g was associated with signification inflammationConclusion: Our study is the first to compare f-Hb and FCP in a paediatric population. Results suggest that f-Hb correlates with FCP and, as in adults, may be useful to rule out significant bowel disease. A f-Hb >20 µg/g was consistent with significant histological inflammation.