The Utility of Faecal Biomarkers in the Discrimination Between Acute Gastroenteritis and Inflammatory Bowel Disease

Background: Acute infectious gastroenteritis (GE) and inflammatory bowel disease (IBD) may have similar clinical characteristics at onset, and discrimination between these two diagnoses can initially be challenging. Aim: To explore faecal biomarkers reflecting neutrophil, eosinophil, and epithelial activity to distinguish between acute GE and IBD onset. Methods: Faecal samples were collected from patients presenting with acute GE (n = 28), treatment-naïve patients with newly diagnosed IBD (n = 40), and healthy controls, HC (n = 40). Faecal biomarkers, including faecal calprotectin (FC), myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN), were assessed by ELISA. The Kruskal-Wallis test was used for biomarker comparisons. To evaluate the discriminative capability of biomarkers, receiver operating characteristic (ROC) curves were established. Result: Patients with acute GE displayed elevated levels of all the tested biomarkers compared with HC (p < 0.001). Higher levels of faecal HNL (p < 0.001), EDN (p < 0.01), and MPO (p < 0.05) were seen in acute GE patients than in patients with newly diagnosed IBD. HNL yielded the highest discriminative capability between acute GE and IBD with AUC 0.74, 95%CI: 0.62-0.84. Conclusions: This exploratory study suggests that faecal biomarkers may provide complementary information in the differentiation of patients with suspected acute GE and new-onset IBD. Our findings indicate that faecal HNL may have the ability to distinguish between these conditions. However, given the exploratory design and limited sample size, findings should be interpreted with caution, and the discriminative value of HNL and the other biomarkers requires further validation in larger, well-characterised acute GE cohorts.