RESUMO
OBJECTIVES: The aim was to evaluate the Elecsys® hCT electrochemiluminescence immunoassay on the immunoanalyser Cobas e411. DESIGN AND 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.
