Screening for iron deficiency anemia in one-year-old infants: hemoglobin alone or hemoglobin and mean corpuscular volume as predictors of response to iron treatment.

Initial screening for anemia was performed on a capillary blood sample in 800 apparently healthy one-year-old white infants. Twenty-six percent had a Hgb or MCV below the estimated tenth percentile of normal and were asked to return for blood counts on a venous sample. They were then started on a three-month course of oral iron. Of the 151 infants who satisfactorily completed the treatment regimen, 54 had a greater than or equal to 1 gm/dl rise in venous Hgb (2.8 infants treated/response). If conformation of the capillary by the venous values had been a prerequisite for treatment, the size of the treatment group would have decreased from 151 to 87, the response rate would have been improved to 2.0 infants treated per response, but 11 of the infants who had a greater than or equal to 1 gm/dl response would have been missed. Since toxicity from iron therapy is rare, either the use of capillary blood counts alone or in combination with venous values constitutes a satisfactory basis for a therapeutic trial of iron in similar populations. Further evaluation can then be reserved for the small number whose Hgb remains below the lower limit of normal after treatment.