title: Distribution of T4 TSH values in children--the Shifa experience.
abstract: OBJECTIVE
  To evaluate the distribution of Thyroxin (T4) and Thyroid Stimulating Hormone (TSH) values in children of various age groups attending our hospital.
  
  
  METHODS
  We have retrospectively reviewed the T4, TSH levels recorded at our hospital in children from birth to 5 years and evaluated the reference intervals for T4 TSH amongst different ages. Non parametric methods were used to establish a 97.5th, 95th, 50th, 5th and 2.5th centiles.
  
  
  RESULTS
  In T4 (n=1148) and TSH (n=1142) samples reviewed a TSH surge following delivery showed a sharp decline in the first 4 days of life. This was followed by a more gradual downward trend. Data on T4 estimations showed a similar but more gradual downward trend in advancing age groups. The 5th-95th centile reference range for TSH showed values between 1.7-22.5 (0-4 days; n=992), 0.6-13.3 (5-7 days; n=38), 0.9-14.0 (1 week-1 month; n=38), 0.5-13.6 (1 month-1 year, n=38) and 0.4-12.8 (1-5 years; n=38) microlU/mL. The 5th-95th centile reference range for T4 showed values between 10.7-25.0 (0-4 days; n=995), 6.5-20.4 (5-7 days; n=35), 8.0-18.1 (1 week-1 month; n=38), 6.0-16.1 (1 month-1 year; n=41), 6.9-15.3 (1-5 years; n=39) micro gm/dl.
  
  
  CONCLUSIONS
  We recommend using separate T4 and TSH reference values for children in different age groups. Further large-scale studies should be done in Pakistan to establish these reference values within age groups. A national center for neonatal thyroid screening is highly recommended.
authors.affiliation: Department of Pediatrics, Shifa International Hospital, Islamabad.
authors.forename: Y
authors.initials: Y
authors.lastname: Najam
authors.forename: M
authors.initials: M
authors.lastname: Khan
authors.forename: F
authors.initials: F
authors.lastname: Ilahi
authors.forename: A
authors.initials: A
authors.lastname: Alam
mesh_terms: D017677:Age Distribution; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D010154:Pakistan / Q000453:epidemiology; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013959:Thyroid Diseases / Q000175:diagnosis / Q000453:epidemiology*; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000032:analysis / Q000378:metabolism*; D013974:Thyroxine / Q000032:analysis / Q000378:metabolism*
chemical_list: D013972:Thyrotropin; D013974:Thyroxine