A 40-year-old man presents with a 3-month history of watery diarrhoea, weight loss and lethargy. Tissue transglutaminase IgA antibodies are strongly positive. What is the most appropriate next step in management?AAdvise starting a strict gluten-free diet immediately without further testsBArrange duodenal biopsy via endoscopy while the patient continues to eat glutenCReassure and repeat antibodies in 1 yearDStart steroids for presumed inflammatory bowel diseaseEAdvise lactose-free diet onlyCheck my answer