title: Multicenter evaluation of the new immunoassay method for TSH measurement using the automated DxI platform.
abstract: OBJECTIVE
  Recently, Beckman Coulter Diagnostics set up a new TSH immunoassay for the automated DxI platform. The aim of this study was to evaluate and compare the analytical performance and clinical results of this method with those of previous method.
  
  
  METHODS
  A multicenter study (named TSH ELAS Study) was organized using 593 serum samples, collected from healthy subjects and patients with thyroid disorders, and 13 control samples, circulated in an External Quality Assessment (EQA) scheme.
  
  
  RESULTS
  The values of LoB and LoD, and LoQ at 20% CV were 0.0004mIU/L, 0.001mIU/L and 0.0023mIU/L, respectively. Moreover, TSH concentrations >0.01mIU/L actually show imprecision values lower than 5% CV. This new TSH assay showed a systematic underestimation (on average of 6.25%) compared to old method, which is mainly due to larger differences between methods for samples with low TSH concentrations, related to the better analytical sensitivity of new compared to old method. In a reference population, including 279 apparently healthy adult subjects, Caucasian volunteers (mean age 43.6years, age 20-63years, 138 women and 141 males) the distribution of TSH concentrations was: mean (CI 95%) 1.694mIU/L (1.588-1.779), median 1.495mIU/L (1.412-1.588mIU/L), 97.5th percentile 3.707mIU/L.
  
  
  CONCLUSIONS
  The new TSH immunoassay for DxI platform shows some relevant improvements compared to the previous one: use of the most recent WHO 3rd IRP 81/563 standard and monoclonal antibodies (instead of polyclonal antibodies of the old method), and better analytical sensitivities and reproducibility.
authors.affiliation: U.O.C. Laboratorio Analisi, Laboratory Medicine Dept., Ospedale dell'Angelo, ULSS 12 Veneziana, Mestre, Venezia, Italy.
authors.forename: Ruggero
authors.initials: R
authors.lastname: Dittadi
authors.affiliation: U.O. Laboratorio Analisi, Laboratory Medicine Dept., Azienda Socio-Sanitaria Territoriale di Cremona, Cremona, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Rizzardi
authors.affiliation: Fondazione CNR-Regione Toscana Gabriele Monasterio and Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Masotti
authors.affiliation: Fondazione CNR-Regione Toscana Gabriele Monasterio and Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Prontera
authors.affiliation: Fondazione CNR-Regione Toscana Gabriele Monasterio and Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ripoli
authors.affiliation: Laboratorio di Chimica Clinica ed Ematologia, Ospedale "San Bortolo", Vicenza, Italy; U.O.C. Patologia Clinica, ASUR Marche Area Vasta 5, Ascoli Piceno, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fortunato
authors.affiliation: Clinical Pathology, Hospital ASL TO4, Ciriè, Turin, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Alfano
authors.affiliation: U.O. Analisi Ormonali e Biologia Molecolare Clinica, Policlinico A. Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Carrozza
authors.affiliation: Clinical Pathology Unit, IRCCS De Bellis, Castellana Grotte, Bari, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Correale
authors.affiliation: Servizio di Medicina di Laboratorio, Ospedale Madonna della Navicella, Chioggia, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Gessoni
authors.affiliation: S.C. Laboratorio Analisi, A.O. Ordine Mauriziano di Torino, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Migliardi
authors.affiliation: QualiMedLab and CNR Clinical Physiology Institute, Pisa, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Zucchelli
authors.affiliation: Fondazione CNR-Regione Toscana Gabriele Monasterio and Scuola Superiore Sant'Anna, Pisa, Italy. Electronic address: clerico@ifc.cnr.it.
authors.forename: Aldo
authors.initials: A
authors.lastname: Clerico
mesh_terms: D000328:Adult; D001331:Automation; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D012016:Reference Values; D015203:Reproducibility of Results; D013964:Thyroid Neoplasms / Q000097:blood; D013972:Thyrotropin / Q000097:blood*; D055815:Young Adult
chemical_list: D013972:Thyrotropin
keywords: Beckman coulter; DxI platform; Immunoassay methods; Quality control; Quality specification; TSH