ABSTRACT
Objective To establish thyrotropin( TSH) and thyroid hormones reference ranges during the neonatal period for the healthy term newborns in Suqian. Methods Blood samples from a heel-prick were collected from 500 healthy newborns 72 hours after birth to determine the level of TSH. 200 healthy newborns were chosen to determine the levels of serum TSH and thyroid hormones on the 14th day of life, and then compared with the results from 120 healthy adults. Results The reference range of TSH at 72 hours after birth was 0. 46-6. 59 mIU/ L. The reference ranges of TT3 , TT4 , TSH, FT3 , FT4 on the 14th day of life were 1. 10-2. 62 nmol/ L, 81. 10-158. 28 nmol/ L, 0. 83-6. 39 mIU/ L, 3. 76-6. 66 pmol/ L, and 10. 67-22. 27 pmol/ L, respectively. There was no significant difference in the interval of TSH between newborns and adluts, whereas there were significant difference in the intervals of TT3 , TT4 , FT3 , and FT4 between the two groups. Conclusions The establishment of TSH and thyroid hormone reference ranges during the neonatal period for the healthy term newborns could improve our understanding of the thyroid function during the neonatal period for the healthy term newborns, and our data suggests lowing the initiatory screening cut-off point of congential hypothyroidism.