A 29-year-old woman has chronic diarrhoea, weight loss and iron-deficiency anaemia. Tissue transglutaminase IgA antibodies are strongly positive. What is the most appropriate next step in confirming the diagnosis?ADuodenal biopsy while continuing a gluten-containing dietBStart a gluten-free diet immediately and recheck antibodies in 6 monthsCColonoscopy and random colonic biopsies onlyDEmpirical steroids for presumed inflammatory bowel diseaseEHydrogen breath test for lactose intoleranceCheck my answer