title: Reference range of thyroid hormones in healthy school-age children: country-wide data from India.
abstract: OBJECTIVE
  This study was planned to obtain normative data of thyroid functions in school-age children from different regions of India.
  
  
  METHODS
  Students from 36 schools involving 13 states across four geographical zones of India were evaluated for goiter. Subjects who consented, underwent evaluation for serum FT3, FT4, TSH, anti-TPO antibodies and thyroid ultrasound. From this, a "reference population" was obtained by excluding those with personal or family history of thyroid disease, use of thyroid medications, goiter, hypoechogenicity or nodularity on ultrasound or positive anti-thyroid antibodies.
  
  
  RESULTS
  Of 24,685 students clinically evaluated, 8665 formed part of the study. The reference population comprised 5343 subjects. The mean, median, 3rd and 97th percentiles of FT3, FT4 and TSH for each year (6-17 years) were obtained.
  
  
  CONCLUSIONS
  This community based study in Indian school-age children provides reference intervals for thyroid hormones and evidence against narrowing the TSH reference range.
authors.affiliation: Department of Endocrinology and Thyroid Research Centre, Institute of Nuclear Medicine and Allied Sciences, Timapur, Delhi-110054, India.
authors.forename: Raman K
authors.initials: RK
authors.lastname: Marwaha
authors.forename: Nikhil
authors.initials: N
authors.lastname: Tandon
authors.forename: Ankush K
authors.initials: AK
authors.lastname: Desai
authors.forename: Ratnesh
authors.initials: R
authors.lastname: Kanwar
authors.forename: Rashmi
authors.initials: R
authors.lastname: Aggarwal
authors.forename: Aparna
authors.initials: A
authors.lastname: Sastry
authors.forename: Satveer
authors.initials: S
authors.lastname: Singh
authors.forename: Archna
authors.initials: A
authors.lastname: Narang
authors.forename: Saroj K
authors.initials: SK
authors.lastname: Ganguly
authors.forename: Kalaivani
authors.initials: K
authors.lastname: Mani
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006042:Goiter / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D012016:Reference Values; D012574:Schools; D013961:Thyroid Gland / Q000378:metabolism; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine