title: [Using newborn congenital hypothyroidism screening specimens to detect iodine deficiency in three regions of Spain].
abstract: BACKGROUND
  Neonatal hyperthyrotropinemia by measurements of thyrotropin (TSH) concentrations has been assessed in three different areas of Spain. The repercussions of a possible iodine deficiency in a congenital hypothyroidism screening program have also been analysed
  
  
  METHODS
  The study comprised 113,108 newborns, which were divided into two groups according to the time of blood sampling. In 78,646 newborns heel blood samples were obtained after 48h whereas in 34,462 newborns, samples were obtained at birth from the umbilical cord (early samples). Newborns came from three areas of the south of Spain, Seville, Huelva and Cordoba. TSH concentrations were measured by time-resolved fluoroimmunoassay.
  
  
  RESULTS
  The percentage of hyperthyrotropinemia was greater in Huelva (5.2%) than Seville (1.0%) (p<0.001), similar to that observed in early samples, which was higher in Huelva (5.3%) than in Seville (1.9%) and Cordoba (1.7%) (p<0.001). In the early samples group, 0.3% and 0.2% of the newborns from Seville and Cordoba respectively, had TSH >20mIU/L and 10 infants should have been recalled for a new sample for each case detected. While in Huelva 17 infants (0.9%) were recalled per case detected.
  
  
  CONCLUSIONS
  The heterogeneous distribution of TSH concentrations in newborns from several geographical areas appears to indicate an irregular and deficient iodine intake. Using early samples and a possible iodine deficiency, increase false positive results in a Neonatal Screening Program of congenital hypothyroidism.
authors.affiliation: Departamento de Bioquímica Clínica, Hospital Universitario Virgen Macarena, Sevilla, España.
authors.forename: T Arrobas
authors.initials: TA
authors.lastname: Velilla
authors.forename: C González
authors.initials: CG
authors.lastname: Rodríguez
authors.forename: A Barco
authors.initials: AB
authors.lastname: Sánchez
authors.forename: C Morales
authors.initials: CM
authors.lastname: Portillo
authors.forename: J A Bermúdez
authors.initials: JA
authors.lastname: de la Vega
authors.forename: S Bernal
authors.initials: SB
authors.lastname: Cerrato
authors.forename: A Gentil
authors.initials: AG
authors.lastname: Baldrich
authors.forename: J M Guerrero
authors.initials: JM
authors.lastname: Montávez
authors.forename: A Sendón
authors.initials: AS
authors.lastname: Pérez
authors.forename: J M González de Buitrago
authors.initials: JM
authors.lastname: Arriero
authors.forename: R Goberna
authors.initials: RG
authors.lastname: Ortiz
mesh_terms: D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology*; D007231:Infant, Newborn; D007455:Iodine / Q000172:deficiency*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin; D007455:Iodine