Neonatal Screening for Hyperthyroidism proof of concept.

The screening thyroid-stimulating hormone test can be used to detect severe NH, the optimal cut-off being 0.18 mIU/L. The additional cost compared to screening for congenital hypothyroidism only would be small. Infants with neonatal hyperthyroidism would benefit from an earlier diagnosis with treatment initiation at the pre-symptomatic stage in many cases, ensuring optimal outcomes.