Nutritional iron deficiency is the most common cause of decreased hemoglobin production in children A peak in the prevalence of iron-deficiency anemia occurs between 12 and 24 months of age, when dietary iron content is often insufficient to meet the demands of a rapidly increasing red cell mass Premature infants are more susceptible to developing iron-deficiency anemia because iron stores at birth are less than those found in term infants, whereas the growth (and therefore, expansion of the red cell mass) of the premature infant is often faster than that of term infants The early exhaustion of iron stores in premature babies may result in pallor by months of age, whereas in normal infants, signs of iron-deficiency anemia are uncommon before 10 to 12 months of age A thorough history and physical examination will provide important clues in the diagnosis of iron-deficiency anemia History suggestive of a lack of iron in the diet may be readily apparent or may be recognized only after careful questioning, particularly regarding the daily consumption of cow’s milk The infant with severe iron deficiency is often irritable and very pale A compensatory increase in cardiac output is seen When coupled with conditions that increase systemic demands on the heart (such as fever), this may provoke the development of congestive heart failure (see Chapter 86 Cardiac Emergencies ) Serum hemoglobin concentration may be as low as g/dL in severe irondeficiency anemia Red blood cells are markedly microcytic and hypochromic, and wide variation in red cell size and shape is usually present Although the percentage of reticulocytes may be elevated moderately, the absolute reticulocyte count is low The diagnosis of iron deficiency as the cause for an anemia can often be made on the basis of the history alone, and treatment is usually instituted before confirmatory laboratory studies are available Free erythrocyte protoporphyrin, a precursor to mature hemoglobin, is increased in iron-deficiency anemia and readily assayed It can be a useful measure when evaluating the severely anemic child in the ED Measurements of serum iron, total iron-binding capacity (TIBC), and ferritin levels can be valuable in the emergency management of anemia if results are rapidly available In hospital systems when the turnaround time is longer, these may serve as helpful confirmatory tests The concentration of hemoglobin in the reticulocyte (CHr) is one of the indices reported with reticulocyte counts, and serves as a sensitive marker of response to iron therapy at outpatient follow-up Other nutritional anemias, such as vitamin B12 or folic acid deficiency, are uncommon in children in the United States When present, these anemias are likely associated with particular conditions such as a grossly altered diet,