Developmental change in red blood cell volume: implication in screening infants and children for iron deficiency and thalassemia trait.

The mean corpuscular volumen when determined by electronic counter is an accurate tool for identification of children with microcytosis due to either iron deficiency or thalassemia trait. The purpose of this report is to describe the normal developmental changes in MCV that occur in children afler 6 months of age. In 211 healthy infants and children screened to exclude those with borderline or overt iron deficiency, thalassemia trait, or hemoglobinopathy, we found that the lower limit of normal for MCV is 70 ft between 10 and 17 months of age and that there is a gradual increase of MCV with age; the lower limit is 74 between 1 1/2 and 4 years and 76 between 4 and 7 years. All of these values are well below the minimum adult level of 80 fl.