A 32-year-old woman presents with intermittent diarrhoea, abdominal bloating and weight loss. She has iron deficiency anaemia. Tissue transglutaminase (tTG) IgA antibodies are strongly positive. What is the most appropriate next diagnostic step?AStart a gluten-free diet immediately with no further investigationBArrange upper GI endoscopy with duodenal biopsiesCOrder CT abdomenDArrange colonoscopy onlyECheck Helicobacter pylori statusCheck my answer