Check both TSH and free thyroxine as measuring TSH alone will miss I central i hypothyroidism. Clinicians should be aware of what congenital hypothyroidism screening method (TSH, FT4 or both) is used in their local area, and be familiar with the limitations of that screening method. FT4, free thyroxine; T4, thyroxine; TRH, thyrotropin-releasing hormone; TSH, thyroid-stimulating hormone. gl Congenital central hypothyroidism is less common (Fig. Thyroid-stimulating hormone (TSH)-based newborn congenital hypothyroidism screening programmes will miss I central i hypothyroidism. [Extracted from the article]