A 36-year-old woman presents with chronic diarrhoea, weight loss and iron-deficiency anaemia. Serology shows elevated anti-tissue transglutaminase IgA. According to Canadian celiac disease guidelines, what is the next best step?AStart a strict gluten-free diet and perform small bowel biopsy to confirm diagnosisBReassure; serology alone is diagnostic and no further tests are neededCOrder colonoscopy to exclude IBD onlyDStart steroids for presumed IBDEAdvise lactose-free diet onlyCheck my answer