A two-screen program for primary congenital hypothyroidism used in Utah meets the goal of not missing cases but not overwhelming the healthcare system with false positive screens, reports a paper published in the Morbidity and Mortality Weekly Report.
Screening for congenital hypothyroidism is generally performed 24 to 48 hours after birth, and 14 states, including Utah, conduct a second routine screening when the infant is approximately 2 weeks old. Researchers conducted a retrospective analysis that covered 7 years (2010 to 2016) of newborn screening data in the state of Utah to evaluate the impact of conducting a second screening on detecting missed cases.
There were a total of 130 confirmed cases of congenital hypothyroidism in Utah during the study period, and 123 cases with 2 screens were analyzed. Of this group, 98 cases were identified by the first screen and 25 by a second screen. The cases were stratified into 2 groups: infants with an abnormal first screen (group 1) and infants with a normal first screen but an abnormal second screen (group 2).
In group 2, thyroid-stimulating hormone (TSH) concentrations were lower on the first screen and below the cutoff value of 40 µIU/mL (range 5.3 to 39.8 µIU/mL), but TSH concentrations were above the cutoff level on the second screen. TSH levels in both groups were significantly elevated on both the first and second screens when compared with all infants who were screened.
“Approximately 20% of congenital hypothyroidism cases were identified through the second screen,” wrote the investigators. “One screen alone could not have identified all of these cases.”
Jones DE, Hart K, Shapira SK, Murray M, Atkinson-Dunn R, Rohrwasser A. Identification of primary congenital hypothyroidism based on two newborn screens – Utah, 2010-2016. MMWR Morb Mortal Wkly Rep. 2018;67(28):782-785.