Serum iron concentration and transferrin saturation in the diagnosis of iron deficiency in children: normal developmental changes.

A group of 359 healthy children and 49 adults were studied for the purpose of estimating the normal limits for serum iron concentration and transferrin saturation. The 144 children and seven adults who has any other laboratory evidence of iron deficiency (abnormal values of serum ferritin, free erythrocyte protoporphyrin, hemoglobin concentration, or mean corpuscular volume) were excluded. In evaluating the 215 children and 42 adults who met the criteria to be considered normal we found that serum iron concentration and transferrin saturation were significantly lower in children between the ages of 0.5 and 12 years than in adults. We conclude that in children between the ages of 0.5 and 12 years, a transferrin saturation of less than 16% constitutes good evidence of iron deficiency only in conjuction with anemia and low mean corpuscular volume.