Serum transferrin receptor for assessment of iron status in healthy prepubertal and early pubertal boys.

A recently introduced test measures the concentration of transferrin receptor (TfR) in serum, which increases shortly after the onset of iron deficiency. In adults this increase reflects the degree to which tissue iron availability is impaired. We developed a fluoroimmunoassay to quantify TfR. The purpose of this study was to evaluate the role of TfR as an index of iron sufficiency in 62 healthy prepubertal or early pubertal boys. The mean concentration of serum TfR was 3.8 (-1 SEM = 3.6, +1 SEM = 3.9) mg/L. No associations were observed between the serum TfR and the concentration of Hb, the values of packed cell volume, reticulocyte production index, mean corpuscular Hb, mean corpuscular volume, or the concentrations of serum iron, transferrin, or ferritin. Because none of the subjects had signs of iron deficiency, we determined the 95% reference intervals for Hb, red blood cell indices, and the above-mentioned serum concentrations. The reticulocyte count and reticulocyte production index were higher than expected. Our results indicated that the individual concentration of TfR in serum does not depend on any of the several other parameters of iron status in a group of healthy individuals.