title: Performance evaluation of an automated electrochemiluminescent calcitonin (CT) immunoassay in diagnosis of medullary thyroid carcinoma.
abstract: OBJECTIVE
  The aim was to evaluate the Elecsys® hCT electrochemiluminescence immunoassay on the immunoanalyser Cobas e411.
  
  
  METHODS
  Within-run, between-run imprecision, linearity, recovery after dilution, the high dose hook effect, as well as the stability of calcitonin were examined. A method comparison to an established immunoradiometric assay was executed in 135 routine plasma samples.
  
  
  RESULTS
  Within- and between-run imprecision CVs were ≤1.4% and ≤2.5%, respectively. The Elecsys® hCT assay was linear over the measuring range of 0.5-2000ng/L. Recoveries after dilution of a high sample in Diluent MultiAssay were within the range of 95% to 97%. The high dose hook point occurred at an hCT concentration of 56,000ng/L. Calcitonin was found to be stable up to 5h at RT, up to 24h at 2-8°C and up to one month at -20° and -80°C. Passing Bablok regression analysis showed no significant deviation from linearity (p=0.10) with a slope of 1.00 (95% CI 0.95-1.06) and an intercept of -0.81 (95%CI -1.01 to -0.46).
  
  
  CONCLUSIONS
  The Elecsys® hCT immunoassay provides precision and reliability in combination with reduced turnaround time as compared to the hCT IRMA.
authors.affiliation: Laboratory of Hormonology and Tumour Markers, Universitair Ziekenhuis Brussel, Free University of Brussels (VUB), Brussels, Belgium. Electronic address: Johan.Schiettecatte@uzbrussel.be.
authors.forename: Johan
authors.initials: J
authors.lastname: Schiettecatte
authors.affiliation: Laboratory of Hormonology and Tumour Markers, Universitair Ziekenhuis Brussel, Free University of Brussels (VUB), Brussels, Belgium.
authors.forename: Olivia
authors.initials: O
authors.lastname: Strasser
authors.affiliation: Laboratory of Hormonology and Tumour Markers, Universitair Ziekenhuis Brussel, Free University of Brussels (VUB), Brussels, Belgium.
authors.forename: Ellen
authors.initials: E
authors.lastname: Anckaert
authors.affiliation: Laboratory of Hormonology and Tumour Markers, Universitair Ziekenhuis Brussel, Free University of Brussels (VUB), Brussels, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Smitz
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D018276:Carcinoma, Medullary / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D009367:Neoplasm Staging; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D002116:Calcitonin
keywords: Calcitonin; Immunoassay