Predicting congenital hypothyroidism in newborns with complex risk profiles by using thyroid-stimulating hormone variations across serial dried blood spots

OBJECTIVES: Newborn screening for congenital hypothyroidism (CH) relies on thyroid-stimulating hormone (TSH) levels from dried blood spots (DBS). We investigated whether incorporating TSH variation across serial DBS could improve prediction of CH in term and preterm infants with complex risk profiles. METHODS: Among 207,895 newborns screened, 272 (0.13 %) were diagnosed with CH. TSH variations across 3 serial DBS were analyzed in 6,146 healthy infants (2.96 %). Predictive algorithms were developed using linear mixed-effects models in 1,968 term and 1,387 preterm infants with ≥2 and ≥3 DBS, respectively. Average DBS collection times were 58, 260, and 478 h for term and 63, 350, and 664 h for preterm infants. TSH was measured by GSP neonatal hTSH assay (Revvity). RESULTS: Daily TSH variation was influenced by the initial DBS1 value. For DBS1 >5.2 and