title: State of the art of aldosterone immunoassays. A multicenter collaborative study on the behalf of the Cardiovascular Biomarkers Study Group of the Italian Section of European Society of Ligand Assay (ELAS) and Società Italiana di Biochimica Clinica (SIBIOC).
abstract: BACKGROUND
  Two new immunoassay methods for aldosterone assay using automated platforms recently became available into market. The main aim of the present study is to evaluate the analytical performance of these automated direct immunoassay methods, and also to compare their analytical characteristics to those of the most popular RIA and EIA methods used in an Italian External Quality Assessment (EQA) study.
  
  
  METHODS
  In this study analytical performances of two aldosterone immunoassays using the IDS iSYS and DiaSorin LIAISON fully automated platforms, were evaluated. Results obtained with the two platforms in EDTA plasma samples of healthy subjects and patients were compared with those obtained by RIA and EIA methods used in the Italian EQA scheme, named Immunocheck study.
  
  
  RESULTS
  The two automated methods showed similar analytical performances: LoD 83.9 vs 92.2 pmol/L, LoQ 104.4 vs 111.1 pmol/L, respectively; moreover, the within-run and total imprecision values showed CV% between 8.1 and 14.1 for samples with 180.8 and 387.2 pmol/L concentration for both methods. There was a close linear regression between methods, however we found a significant proportional bias between LIAISON and iSYS methods. The EQA samples results obtained with these two methods were highly correlated to the consensus mean values.
  
  
  CONCLUSIONS
  Our data indicate that aldosterone values measured with the two automated methods actually show better reproducibility, shorter laboratory Turn Around Time (TAT) and require less "hands on labor" compared to RIA and EIA immunoassays. However, in our study significant bias was observed in result comparison, this means that translating aldosterone concentration in clinical information an appropriate definition of reference ranges for each method is mandatory.
authors: Clinical Chemistry and Hematology Laboratory, San Bortolo Hospital, Viale F. Rodolfi, 37, Vicenza, Italy. Electronic address: antonio.fortunato@ulssvicenza.it.
authors: Antonio
authors: A
authors: Fortunato
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: tina@ftgm.it.
authors: Concetta
authors: C
authors: Prontera
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: silvi87@gmail.com.
authors: Silvia
authors: S
authors: Masotti
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: franzinimaria@gmail.com.
authors: Maria
authors: M
authors: Franzini
authors: Clinical Chemistry and Hematology Laboratory, San Bortolo Hospital, Viale F. Rodolfi, 37, Vicenza, Italy. Electronic address: cristina.marchetti@ulssvicenza.it.
authors: Cristina
authors: C
authors: Marchetti
authors: QualiMedLab srl, Via G. Moruzzi 1, Pisa, Italy. Electronic address: stefania@ifc.cnr.it.
authors: Stefania
authors: S
authors: Giovannini
authors: QualiMedLab srl, Via G. Moruzzi 1, Pisa, Italy. Electronic address: zucchell@ifc.cnr.it.
authors: Gian Carlo
authors: GC
authors: Zucchelli
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: emdin@ftgm.it.
authors: Michele
authors: M
authors: Emdin
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: passino@ftgm.it.
authors: Claudio
authors: C
authors: Passino
authors: Department of Cardiovascular Medicine and Laboratory Medicine, Fondazione CNR-Regione Toscana G. Monasterio, Via G. Moruzzi 1, Pisa, Italy. Electronic address: aldo.clerico@ftgm.it.
authors: Aldo
authors: A
authors: Clerico
mesh_terms: D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007558:Italy; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015415:Biomarkers; D000450:Aldosterone
keywords: Aldosterone; External quality control; Immunoassays methods; RIA