Original articlesFollow-up of newborns with elevated screening T4 concentrations
Section snippets
Methods
Infants born in Oregon and undergoing newborn screening were eligible for the study. T4 screening tests are carried out by the Oregon State Public Health Laboratory (PHL) on approximately 350 Oregon infants daily. Two routine screening specimens are collected in Oregon, the first at approximately 2 days of life and the second at approximately 2 weeks of life. As the serum TT4 rises and peaks 24 hours after birth and then falls over the next week of life, samples collected at approximately the
Results
Over a 20-month period, we enrolled 101 infants (51 boys) into the study of 241 eligible infants whose mothers were offered participation, from a total screening population of 80,884 infants born in Oregon over that time. Of the 101 infants who participated, 17 had persistent TT4 elevation confirmed on serum testing, whereas the serum TT4 measurement in the other 84 infants was normal. A comparison of the screening test results in the 17 infants with persistent hyperthyroxinemia and the 84
Discussion
Overall, we detected 17 infants with confirmed hyperthyroxinemia of 80,884 newborn infants. The incidence of these combined disorders is approximately 1 in 4750, which, as described above, probably is an underestimate. Our main goal in follow-up of newborn infants with elevated screening T4 concentrations was to detect infants with some form of hyperthyroidism who would benefit from early detection and treatment. However, we did not detect any infant with unrecognized neonatal Graves' disease
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