title: Screening for hypothyroidism in Down syndrome using the capillary thyroid stimulating hormone method.
abstract: OBJECTIVE
  To analyze data from the Scottish capillary thyroid stimulating hormone (TSH) screening program for hypothyroidism in Down syndrome to identify a threshold for capillary TSH elevation below which low venous free thyroxine (fT4) (<9 pmol/L) and/or frank venous TSH elevation (>10 mU/L) range is unlikely.
  
  
  METHODS
  Review of proformas prospectively submitted on all children with Down syndrome referred via the screening program between 2003 and 2013.
  
  
  RESULTS
  Ninety-nine patients with Down syndrome (50 females, 49 males) were identified, 76 school-age (≥ 5 years) and 23 preschool (<5 years), mean (range) age at referral 9.4 (0.9-18.1) years. Pearson correlation between capillary TSH and venous TSH was 0.814; between capillary TSH and venous fT4 -0.522 (P = .01). Receiver operator curve analysis showed that capillary TSH values of 4 and 6 mU/L were 95.9% and 73.5% sensitive, 5.8% and 80.8% specific, respectively, in predicting venous TSH >10 mU/L. Fifty-three children had capillary TSH values of 4-5.9 mU/L of whom only one, a boy of 15.8 years, had subnormal venous fT4 (<9 pmol/L), and venous TSH >10 mU/L was found in 13 (4 preschool).
  
  
  CONCLUSIONS
  Venous fT4 is normal in almost all patients with Down syndrome with capillary TSH 4-6 mU/L. We propose an algorithm incorporating rescreening by finger prick after 6 months, rather than venepuncture, in school-aged children with borderline capillary TSH elevation. Further data are needed before this approach can be recommended for preschool children.
authors: Section of Child Health, Royal Hospital for Sick Children, University of Glasgow School of Medicine, Yorkhill, Glasgow, United Kingdom.
authors: Sheena
authors: S
authors: McGowan
authors: National Health Service Greater Glasgow and Clyde, Royal Hospital for Sick Children, Yorkhill, Glasgow, United Kingdom.
authors: Jeremy
authors: J
authors: Jones
authors: Academic Unit of Surgery, Glasgow University School of Medicine, Royal Infirmary, Glasgow, United Kingdom.
authors: Donald
authors: D
authors: McMillan
authors: National Health Service Greater Glasgow and Clyde, West of Scotland Genetic Services, Newborn Screening Laboratory, Southern General Hospital, Glasgow, United Kingdom.
authors: Kirsty
authors: K
authors: McLaughlin
authors: National Health Service Greater Glasgow and Clyde, West of Scotland Genetic Services, Newborn Screening Laboratory, Southern General Hospital, Glasgow, United Kingdom.
authors: Sarah
authors: S
authors: Smith
authors: National Health Service Greater Glasgow and Clyde, Southbank Development Center, Glasgow, United Kingdom.
authors: Kath
authors: K
authors: Leyland
authors: National Health Service Grampian, Royal Aberdeen Children's Hospital, Aberdeen, United Kingdom.
authors: Patricia
authors: P
authors: Charleton
authors: Section of Child Health, Royal Hospital for Sick Children, University of Glasgow School of Medicine, Yorkhill, Glasgow, United Kingdom. Electronic address: malcolm.donaldson@glasgow.ac.uk.
authors: Malcolm
authors: M
authors: Donaldson
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening / Q000379:methods*; D015995:Prevalence; D012189:Retrospective Studies; D012606:Scotland / Q000453:epidemiology; D013960:Thyroid Function Tests / Q000379:methods*; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin