Sudden infant death syndrome and hypertriiodothyroninemia: comparison of neonatal and postmortem measurements.

Serum triiodothyronine concentrations in victims of sudden infant death syndrome, when compared with those of both living and dead controls, were found to be elevated to a degree comparable to those found in a previous study. Thyroxine, thyroid-stimulating hormone, and thyroglobulin values were not elevated. Neonatal triiodothyronine and thyroxine values, determined on specimens collected within a few days of birth for most of the sudden infant death syndrome victims, did not differ significantly from those of comparable peers in their birth cohort. These results indicate that hypertriiodothyroninemia may serve as a useful postmortem diagnostic marker for the syndrome but not as a premortem predictor. Parenthetically, thyroid hormones appear to remain stable in either a frozen or dried state for up to two years.