title: Neonatal screening for congenital hypothyroidism based on thyroxine, thyrotropin, and thyroxine-binding globulin measurement: potentials and pitfalls.
abstract: BACKGROUND
  The Dutch T(4)-TSH-TBG-based neonatal screening program detects patients with congenital hypothyroidism (CH) of thyroidal (CH-T) as well as central (CH-C) origin. The numbers and characteristics of true-positive and false-positive referrals will differ from other, predominantly TSH-based, screening methods.
  
  
  OBJECTIVE
  The present study describes the characteristics of the referred neonates, both CH patients and false positives, and of the reported CH patients with a false-negative screening result born in the study period.
  
  
  METHODS
  For each referred child born between April 1, 2002, and May 31, 2004, screening results and first venous sample results were recorded and classified as transient or permanent CH-T or CH-C or as no CH.
  
  
  RESULTS
  In the study period, 430,764 children were screened. Of the 772 children with abnormal screening results, 224 (29%) had CH; another 13 CH patients did not have abnormal screening results, giving an overall CH incidence of 1:1800. Incidences of permanent CH, permanent CH-T, permanent CH-C, and transient CH were 1:2200, 1:2500, 1:21,000, and 1:12,000, respectively. The most frequent explanations for the 548 false-positive referrals (71% of the referred cohort) were severe illness and TBG deficiency (occurring in 198 and 200 children, respectively).
  
  
  CONCLUSIONS
  The Dutch incidence figures for CH belong to the highest worldwide, suggesting that the T(4)-TSH-TBG screening program is an efficient method to detect CH of variable etiology and severity. Still, a small percentage of children with CH escaped detection via this screening approach. Severe illness and TBG deficiency appear to be responsible for the majority of false-positive referrals.
authors.affiliation: Academic Medical Center, University of Amsterdam, G8-205, Emma Children's Hospital AMC, Department of Pediatric Endocrinology, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands. m.j.kempers@amc.uva.nl
authors.forename: M J E
authors.initials: MJ
authors.lastname: Kempers
authors.forename: C I
authors.initials: CI
authors.lastname: Lanting
authors.forename: A F J
authors.initials: AF
authors.lastname: van Heijst
authors.forename: A S P
authors.initials: AS
authors.lastname: van Trotsenburg
authors.forename: B M
authors.initials: BM
authors.lastname: Wiedijk
authors.forename: J J M
authors.initials: JJ
authors.lastname: de Vijlder
authors.forename: T
authors.initials: T
authors.lastname: Vulsma
mesh_terms: D003409:Congenital Hypothyroidism / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000379:methods*; D009426:Netherlands / Q000453:epidemiology; D013954:Thyroglobulin / Q000097:blood; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D013954:Thyroglobulin; D013974:Thyroxine