INTRODUCTION: International recommendations suggest that when laboratories begin to use a new measurement procedure, the analytical performance of the new procedure should be evaluated. In this study, we evaluated the analytical performance of the Vidas 3 high sensitivity cardiac troponin I assay.
METHODS: The precision, linearity, and measurement procedure comparison study were performed according to international standardized protocols (EP15-A3, EP06-A and EP09c). Serum samples were analyzed 20 times and at a frequency of three runs/day on five consecutive days for the calculation the CV% of repeatability and within-laboratory precision. The highest concentration hs-cTnI calibrator was diluted for the preparation of five pools with a concentration range of 9.6–16450 ng/L. The Beckman Dxl 800 analyzer was chosen as the comparative measurement procedure.
RESULTS: For low- and high-level concentrations, CV% of repeatability was calculated as 3.12 and 4.74; CV% of within-laboratory precision was calculated as 3.04 and 2.07, respectively. The linear regression analysis showed a line with a good correlation coefficient (r>0.99) over the entire range tested. PassingBablok regression was described with the equation y=0.2995+1.006 x. There was no significant deviation from linearity (p=0.800). The 95% confidence interval of the intercept value and slope value was calculated as -1.3734 to 1.0214 and 0.9973 to 1.022, respectively. The mean absolute difference was -12.1ng/L (95% CI=-24.2479 to 0.0979).
DISCUSSION AND CONCLUSION: Vidas 3 hs-cTnI measurement procedure is a precise and linear method for the determination of hs-cTnI. There is no significant difference between Vidas 3 and the Beckman Dxl 800 measurement procedure.