16. Respone to iron therapy Time after Fe administration Respone 12-24 hr Replacement of intracellular Fe enzymes, decrease irritability, increase appetite 36-48 hr Initial bone marrow response, erythroid hyperplasia 48-72 hr Reticulcytosis, peaking at 5-7 days 4-30 hr Increase in Hb level > 1 month Repletion of tore