Best marker for iron deficiency is
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.
Serum iron
Serum ferritin
Total iron binding capacity
Transferrin saturation
Haematology