<prompt> A Patient presents with macroglossia and loss of tongue papilla. His hemoglobin Hb is 11.5 and mean corpuscular volume MCV is 100. What should be the next step in investigating this patient?B12 estimationBrush biopsy of the lesionFluconazole treatmentIncision biopsy  <response>: Increased MCV normal MCV 79- 93.3, anemia normal Hb 12--16.2 and characteristic oral manifestation macroglossia and Atrophy of Papillae suggest the diagnosis of megaloblastic anemia. The next best step is to confirm the diagnosis by estimating vitamin B12 levels and folate levels. So B12 estimation is the single best answer of choice. Ref: Harrisons Principles of Internal Medicine, 16th Edition, Pages 602-03; Davidsons Principles and Practice of Medicine, 19th Edition, Pages 918-20; Manual of Practical Medicine By R Alagappan, 3rd Edition, Pages 327-29 