National survey on concepts for congenital hypothyroidism screening in neonatal intensive care units in Japan.

BACKGROUND: Recently, a revised version of the Guidelines for Mass Screening of Congenital Hypothyroidism (CH) was published in Japan, but it is not known whether the guidelines are used routinely in neonatal intensive care units (NICU).

METHODS: To clarify the current status and issues of newborn screening (NBS) for CH in Japanese NICU, we sent a questionnaire by mail or email to neonatologists responsible for 100 tertiary NICU in Japan, and analyzed their responses.

RESULTS: The response rate was 92% (92/100). Among respondents, 65% (59/91) performed thyroid function testing separately from NBS for CH. Within this group, 63% (37/59) applied criteria, mostly for very low-birthweight (VLBW) infants (25/37). Only 29% of respondents (26/90), however, used criteria to select VLBW infants for treatment. Furthermore, criteria differed in each NICU. Fifty-seven percent of respondents (50/87) reported issues regarding NBS for CH in NICU, which fell into three main areas: establishment of a clear method for the management of VLBW infants; necessity of simultaneous measurement of thyroid-stimulating hormone and free thyroxine; and overlapping blood collection for NBS and thyroid function tests.

CONCLUSIONS: Two-thirds of tertiary NICU performed thyroid function testing separately from NBS for CH. Approximately 60% of neonatologists responded that current NBS for CH had ongoing issues. Further research is needed to establish the optimal NBS protocol for CH in NICU in Japan.