NORMAL VALUES OF SERUM PROTEIN BOUND IODINE IN HEALTHY CHILDREN AGED BETWEEN 4 AND 13 YEARS; BIOCHEMICAL EVIDENCE FOR THE EXISTENCE OF THE JUVENILE OR MID-GROWTH SPURT

Abstract

Protein bound iodine (PBI) was determined in 379 serum specimens of boys and girls, aged between 4 and 13 years. From this investigation it can be seen that: (a) there is no significant difference in the PBI concentration between boys and girls of the same age group, (b) in general the PBI concentration decreases with increasing age (1.4 μ/l/year), (c) both for boys and for girls there is a significant increase in the PBI concentration from the sixth year to the seventh year of age, a result which coincides with the juvenile or mid-growth spurt, and (d) the normal range, calculated from all data, amounts to 40.7–71.1 μg/l (mean value ± 2x standard deviation).