Elevated thyroid-stimulating hormone level in a euthyroid neonate caused by macro thyrotropin-IgG complex.

Unlabelled: Elevated thyroid-stimulating hormone (TSH) was discovered by routine neonatal screening in a newborn with no clinical symptoms. Thyroid function tests were repeated and confirmed a high TSH value but normal total thyroxine (T4) and triiodothyronine (T3). However, the mother also had elevated serum TSH with normal levels of T4 and T3.