Targeted Secondary Screening for Congenital Hypothyroidism in High-Risk Neonates: A 9 Year Review in a Large California Health Care System

Abstract

Secondary screening for missed congenital hypothyroidism (CH) has been introduced sporadically, but its necessity and optimal strategy have not been recognized. We hypothesized that a simple clinical protocol (performed by a medical group without a governmental mandate) targeting infants at high risk for missed CH can identify cases. We performed a 9-year retrospective review of 338,478 neonates within a California health plan following the introduction of thyrotropin (TSH) secondary screening for neonates at high risk for missed CH due to very-low-birthweight (VLBW), hospitalized congenital heart disease (CHD), and same-sex multiples (SSM). Screening performance by day 60 of life was 95% successful for VLBW and >50% for CHD and SSM, leading to an additional 35% CH treated cases despite re-testing only 1.7% of the cohort. Infants with VLBW or CHD were 33 times more likely (190 times more likely for CHD with Down Syndrome) to receive treatment for CH than random infants diagnosed by primary screening (p p < 0.001). This targeted secondary screening program identifies and treats additional CH cases after TSH-only newborn screening.

Keywords

• neonatal screening
• congenital hypothyroidism
• thyrotropin
• infant
• newborn
• infant