Аннотация:We read with interest the case reported by Newman et al. (1) of factitious neonatal hyperthyrotropinemia, and we noted that the authors were unable to identify the maternally transmitted interfering substance. We report a similar case in which we demonstrated that the interference was caused by the presence of a macro thyrotropin-IgG complex (macroTSH).
Routine neonatal screening performed 7 days after an uncomplicated delivery in a full-term infant revealed a blood spot thyroid-stimulating hormone (TSH) of 213 mIU/L (Perkin-Elmer DELFIA assay, reference range <10 mIU/L). The neonate was clinically euthyroid, and repeat serum thyroid function tests at 10 days (Roche Elecsys) confirmed the increased serum TSH (826 mIU/L, reference interval 0.27–4.20 mIU/L) but showed a free thyroxine (FT4) concentration within the reference interval, at 17.2 pmol/L (reference interval 12.0–22.0 …
