title: An approach to establish reference intervals for thyrotropin in pregnancy using the ADVIA Centaur analyzer.
abstract: BACKGROUND
  Reference values for thyrotropin (TSH) from weeks 5 to 17 of pregnancy in women living in a moderately iodine-deficient area in Italy have never been calculated using the Advia Centaur analyzer.
  
  
  METHODS
  TSH was measured in surplus blood samples drawn from 657 pregnant women: 101 in weeks 5-6 (group I), 333 in weeks 7-8 (group II), 139 in weeks 9-10 (group III), 44 in weeks 11-12 (group IV), and 40 in weeks 13-17 (group V) of pregnancy. Health-Related Limits (HRLs) were calculated with GraphROC software using the indirect Kairisto's procedure and the "robust method" advocated by the CLSI C28-A3 Guideline.
  
  
  RESULTS
  The HRLs of TSH concentration (indirect method) were 0.36 - 3.78 mU/L in group I, 0.19 - 3.07 mU/L in group II, 0.23 - 2.90 mU/L in group III, 0.13 - 3.28 mU/L in group IV, and 0.45 - 3.90 mU/L in group V. The Upper Reference Limit calculated using the robust method decreased in group II-IV and increased in group V.
  
  
  CONCLUSIONS
  TSH concentration decreases in the second half of the first trimester of pregnancy and increases in the second trimester. The indirect method is reliable for calculating HRLs for TSH in pregnancy, as confirmed by the robust method. The TSH concentrations in group I were statistically different from those of groups II, III, and IV, but not of those of group V.
authors.affiliation: U.O.C. Corelab, Laboratorio Unico di AvR, Pievesestina, Cesena (FC), Italy. rdorizzi@ausl-cesena.emr.it
authors.forename: Romolo M
authors.initials: RM
authors.lastname: Dorizzi
authors.forename: Giulio
authors.initials: G
authors.lastname: Ozzola
authors.forename: Ciro
authors.initials: C
authors.lastname: Sommella
authors.forename: Francesco
authors.initials: F
authors.lastname: Catania
authors.forename: Franco
authors.initials: F
authors.lastname: Lelli
authors.forename: Ettore
authors.initials: E
authors.lastname: Migali
authors.forename: Graziana
authors.initials: G
authors.lastname: Polverini
mesh_terms: D002681:China; D005060:Europe; D005260:Female; D006304:Health Status; D006801:Humans; D007558:Italy; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology*; D011262:Pregnancy Trimester, Second / Q000502:physiology*; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014416:Tunisia
chemical_list: D013972:Thyrotropin; D013974:Thyroxine