A 68-year-old woman presents with fatigue and dyspnoea on exertion. Hb is 90 g/L, MCV 72 fL and ferritin is 8 µg/L. She has no obvious menstrual loss. What is the most appropriate next step after confirming iron deficiency?AStart oral iron and no further investigationsBArrange upper and lower gastrointestinal endoscopy to identify occult blood lossCRefer immediately for bone marrow biopsyDStart erythropoietin therapyENo treatment is needed for mild anaemiaCheck my answer