Percentile estimates for transferrin receptor in normal infants 9-15 mo of age.

To establish percentile estimates of transferrin receptor (TfR) for healthy infants, plasma TfR was measured in 485 healthy infants 9-15 mo of age from Edmonton, Toronto, Montreal, and Halifax. Education and income of the sample families were reflective of the average family based on the 1991 census estimates. The mean (+/-SD) plasma TfR concentration was 4.4 +/- 1.1 mg/L. As expected in the infant population, there were no differences in TfR concentrations as a result of sex, and within this small age range there was no significant change across age. Furthermore, the TfR concentration in plasma was not associated with hemoglobin, serum ferritin, or free erythrocyte protoporphyrin. TfR has been shown to be a sensitive, quantitative measure of tissue iron deficiency not affected by inflammation and is potentially important in the diagnosis of iron deficiency, but there is a lack of normative data, particularly in infants, who are at highest risk of iron deficiency. If TfR proves useful in the diagnosis of iron deficiency, the current data will be useful as a reference standard for healthy infants.