Kaluarachchi DC, et al. - Because information on thyroid-stimulating hormone (TSH) reference ranges in preterm infants at increasing postnatal age are insufficient, researchers determined TSH reference ranges for preterm infants born at < 32 weeks’ gestation. On infants born between 22 and 31 weeks’ gestation from 2012 to 2016 in Wisconsin, they evaluated serial TSH levels on NBS. The study sample consisted of 1,022 and 2,115 infants born at 22 to 27 and 28 to 31 weeks’ gestation, respectively. The authors built TSH reference charts from birth to the term equivalent gestation for preterm infants born at < 32 weeks’ gestation using a statewide cohort of preterm infants. Using a single cutoff may lead to misdiagnosis for all preterm infants. Differences in TSH levels according to categories of gestational age may explain the increased frequency of preterm infant diagnoses of congenital hypothyroidism. These data are helpful in identifying preterm infants' age-adjusted NBS TSH cutoffs.