A 29-year-old woman has chronic tiredness and iron-deficiency anaemia. Coeliac serology shows positive tissue transglutaminase (tTG) IgA antibodies. What is the most appropriate next step?AStart a gluten-free diet immediately without further investigationBRefer for duodenal biopsy while she remains on a gluten-containing dietCRepeat serology after starting iron therapyDLabel her as having non-coeliac gluten sensitivityEDischarge with reassuranceCheck my answer