Precision performance at low levels and 99th percentile concentration of the Access((R)) AccuTnI((R)) assay on two different platforms.

Background: Cardiac troponins currently represent the preferred biomarkers for the detection of myocardial necrosis. The objective of the present study was to compare the performance of the Access (R) AccuTnI (R) assay (Beckman Coulter) measured on two different platforms, the UniCel (R) DxI 800 and the Access (R) 2 (Beckman Coulter). In particular, the serum cardiac troponin I (cTnI) concentration corresponding to 10% coefficient of variation (CV), the cTnI assay minimum detectable concentration (MDC), and the serum cTnI 99th percentile in healthy subjects were calculated. Methods: The Access (R) AccuTnI (R) is a paramagnetic particle chemiluminescent immunoassay. Imprecision profiles were determined according to the Clinical and Laboratory Standards Institute EP5-A protocol using serum pools. The MDC was calculated as mean + 3 SD of 20 determinations of the zero calibrator during one run. The 99th percentile was determined analyzing serum samples from 679 healthy blood donors (523 males, 156 females; 18-71 years old). Results: cTnI concentrations are given in mg/L. 10% CV values (95% confidence interval, CI) were 0.0577 (0.0467-0.0750) (UniCel (R) DxI 800) and 0.0486 (0.0255-0.0596) (Access (R) 2). MDC values were 0.011 (UniCel (R) DxI 800) and 0.012 (Access (R) 2). The 99th percentile (95% CI) value was 0.0340 (0.0298-0.0410). Conclusions: Our data confirm the reliability of the evaluated cTnI assay and demonstrate the comparability of the cTnI values between the platforms studied.