Serum thyroglobulin levels: the physiological decrease in infancy and the absence in athyroidism.

The cord serum thyroglobulin levels of 218 neonates are much higher than the levels after the first year of life and show a wide range. A relation exists between a shorter gestational age and increased thyroglobulin levels. The serum thyroglobulin levels decrease within a few months after birth, but throughout the first year of life, these levels are still higher than the normal values at later ages (5-35 ng/ml). IN 3 athyroid children, thyroglobulin is undetectable in serum.