Determining Reference Ranges for Total T 4 in Dried Blood Samples for Newborn Screening.

Authors :: Hijman AI
Konrad D
Fingerhut R
Source :: International journal of neonatal screening [Int J Neonatal Screen] 2020 Mar 04; Vol. 6 (1), pp. 17. Date of Electronic Publication: 2020 Mar 04 (Print Publication: 2020).
Publication Year :: 2020
Abstract: The purpose of this study was to define reference intervals for total thyroxine (tT <subscript>4</subscript> ) in dried blood samples (DBSs) obtained for newborn screening. The aim of our study was to assess the possible benefit of measuring tT <subscript>4</subscript> concentrations directly in DBSs obtained for newborn screening in premature and term-born infants. In order to have a sufficient number of samples for the extremely premature infants (<30 weeks), we set up a retrospective study, measuring the concentrations in DBSs collected over the previous 21 weeks. This time frame was a result of the included miniature study of tT <subscript>4</subscript> stability in DBSs. We found that tT <subscript>4</subscript> strongly correlated with gestational age (GA) in premature infants, highlighting the need for age-specific reference ranges. For term-born infants, the tT <subscript>4</subscript> ranges did not vary significantly among different gestational ages, allowing for the use of one single reference range.<br />Competing Interests: Conflicts of InterestThe authors declare no conflict of interest.<br /> (© 2020 by the authors.)

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