Abstract

The ¹³¹I triiodothyronine (T₃) resin uptake test reflects thyroid function more closely than other acceptable tests currently available.

The T₃ uptake and protein-bound iodine (PBI) level were estimated in 20 premature and 20 full-term infants at birth and at the end of 1 week.

The full-term infant has normal adult values, whereas the premature baby has results extending into the hyperthyroid range at birth, but these fall to within normal limits at 1 week.