A 34-year-old woman with chronic diarrhoea and bloating is suspected of having coeliac disease. She has been avoiding gluten for several weeks. Which is the most appropriate next step in investigation?AReintroduce gluten into her diet and arrange coeliac serology (tissue transglutaminase IgA) while she is consuming glutenBPerform coeliac serology while she continues on a strict gluten-free dietCStart a gluten-free diet permanently without further testingDOrder HLA typing alone and base diagnosis on HLA resultEArrange colonoscopy onlyCheck my answer