title: Reference intervals for serum thyroid hormones in preterm hospitalized infants.
abstract: OBJECTIVE
  In our study, the reference intervals of serum thyroid hormones were established in 247 hospitalized preterm infants from 28 to 36 weeks of gestation at 8-15 postnatal days. The thyroid hormones were serum triiodothyronine (T3), free triiodothyronine (FT3), thyroxine (T4), free thyroxine (FT4), and thyrotropin (TSH).
  
  
  METHODS
  Electrochemiluminescence immunoassay was used to examine the thyroid hormone levels of serum samples from 247 preterm infants, who were grouped on sampling by gestational age. SPSS 16.0 was used to calculate the population-based reference intervals, in comparison to the manufacturer's suggested reference intervals.
  
  
  RESULTS
  Kruskal-Wallis H tests could not determine the difference in TSH levels among groups, which allowed us to develop a single interval for the study population. ANOVA determined the differences in T3, FT3, T4, and FT4 levels among groups, which allowed us to define reference intervals for preterm infants according to their gestational age.
  
  
  CONCLUSIONS
  Developed reference intervals are useful for clinical diagnosis; however, there is a lack of consensus. These values could be used to assess the thyroid status of preterm infants and provide a foundation for clinical therapy. The results emphasized the importance of establishing gestational age-based reference intervals for the clinical laboratory.
authors: Department of Pediatrics, BaYi Children's Hospital of The General Military Hospital of Beijing PLA, Beijing 100700, PR China.
authors: Lina
authors: L
authors: Zhu
authors: Xiaoying
authors: X
authors: Zhang
authors: Xiyu
authors: X
authors: He
authors: Xiao
authors: X
authors: Yang
authors: Yan
authors: Y
authors: Wang
authors: Chunzhi
authors: C
authors: Wang
authors: Zhichun
authors: Z
authors: Feng
mesh_terms: D002624:Chemistry, Clinical / Q000379:methods / Q000592:standards*; D002673:Child, Hospitalized; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D012016:Reference Values; D012189:Retrospective Studies; D013960:Thyroid Function Tests / Q000379:methods / Q000592:standards*; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine