Vijayvargiya P, et al. - In patients with irritable bowel syndrome with diarrhoea (IBS-D), constipation (IBS-C) and healthy controls, researchers identified differences in faecal bile acids, faecal fat and fasting serum C4 (7a-hydroxy-4-cholesten-3-one) and fibroblast growth factor 19 (FGF19) and determined precise, cost-effective biomarkers for clinically relevant diarrhoea and constipation. Daily stool frequency and consistency (Bristol Stool Form Scale) were evaluated from validated bowel diaries, 48 hours total and individual faecal bile acids, 48 hours faecal fat and weight, fasting serum C4 and FGF19, and colonic transit by scintigraphy from healthy volunteers (HV) and patients with IBS-D and IBS-C (Rome III criteria). The combination of faecal biomarkers is $485 for identifying diarrhoea and $237 for identifying constipation at the current charges. Among IBS-D and IBS-C patients, faecal bile acids and faecal fat are cost-effective and accurate biomarkers related to significant bowel dysfunction.