<prompt> Best marker for iron deficiency isSerum ironSerum ferritinTotal iron binding capacityTransferrin saturation  <response>: Ref Harrison 19 th ed pg 627-628 The serum ferritin level is a better indicator of iron overload than the marrow iron stain. However, in addition to storage iron, the marrow iron stain provides information about the effective delivery of iron to develop- ing erythroblasts. 