How well does the capillary thyroid-stimulating hormone test for newborn thyroid screening predict the venous free thyroxine level?

摘要

Objectives To determine, in newborn infants referred with elevated capillary thyroid-stimulating hormone (TSH), a threshold below which a frankly subnormal venous free thyroxine (fT4) level of < 10 pmol/L is unlikely, so that treatment with levo-thyroxine (L-T4) might be deferred until venous thyroid function tests (TFTs) become available.