A Study of the Blood Iodine in Childhood.

The recent development of adequate techniques for the microdetermination of iodine in biological material has given impetus to the study of iodine metabolism in health and disease. Within the past ten years many studies of the range of blood iodine in normal and pathological conditions have appeared in the literature (1, 2). Unfortunately, the "normal" whole blood iodine values given by various authors vary widely, ranging from an average of 4.3 micrograms per 100 cc. of blood reported by Fowweather (3) to Widmann's (4) reported average of 32 micrograms per 100 cc. Such wide discrepancies may be attributable, in part, to different analytical methods employed and partly to varying locale. In spite of the lack of agreement upon a normal blood iodine milieu, most authors concur in finding a frequent correlation, although by no means an absolute parallelism, between the level of iodine in the blood and the functional activity of the thyroid gland. The present study was undertaken: 1, to establish, in the absence of adequate normal standards for blood iodine in children, such norms on a large number of subjects; 2, to investigate the effect of a number of variables such as age, type of feeding, season and fever on the level of blood iodine in these subjects in an effort to define optimal conditions for making analyses; 3, to assay the diagnostic possibilities of the blood iodine in thyroid disturbances. The latter is of special interest since direct metabolic measurements are technically difficult in infants and young children.