Background: The determination of cardiac troponins is routinely used for rule in/out, risk stratification, and follow-up of patients with acute coronary artery syndrome. We evaluated the analytical and clinical performance of the advanced immunoassay for troponin I (cTnI) carried out on an AxSYM platform (Abbott Diagnostic Division) and compared these characteristics to those of the previous version of this assay and to cTnI on the Access 2 immunoassay system (Beckman Coulter, Inc.). Methods: We assayed plasma samples from healthy subjects (n=66) and cardiac patients (n=132) using AxSYM Plus system assays called the old (OLD Ax- SYM) and advanced TnI (ADV AxSYM) methods and using an Access system. Results: An improvement in analytical sensitivity (detection limit) was observed for the advanced cTnI AxSYM compared to the previous method (0.014 vs. 0.31 mg/L), while the cTnI value for the 10% CV (i.e., functional sensitivity) was 0.41 mg/L for the ADV and 1.9 mg/L for the OLD method. The kinetics of cTnI release was similar, as evaluated in 25 patients with typical acute myocardial infarction (AMI). A close linear relationship was found between the two methods on the AxSYM system (OLD cTnI=7.436+6.858 ADV cTnI; R=0.968, n=214) and with the Access system (OLD AxSYM=7.154+7.9 Access, R=0.876, n=158; ADV AxSYM=0.23+1.209 Access, R=0.927, n=160). However, wide bias was found between the OLD and ADV AxSYM methods (mean difference 118.4 mg/L, p0.0001), while more similar results were found between the ADV AxSYM and Access methods (mean difference 2.6 mg/L, corresponding to a mean percentage difference of 17%, p0.0001). In 106 patients with symptomatic rheumatoid arthritis with high rheumatoid factor (RF) concentration, the mean cTnI measured by the ADV AxSYM method was 0.009± 0.031 mg/L (range 0-0.23 mg/L) with a significant correlation (R
Evaluation of the analytical performance of the advanced method for cardiac troponin I for the AxSYM platform: comparison with the old method and the access system
Storti S;
2006
Abstract
Background: The determination of cardiac troponins is routinely used for rule in/out, risk stratification, and follow-up of patients with acute coronary artery syndrome. We evaluated the analytical and clinical performance of the advanced immunoassay for troponin I (cTnI) carried out on an AxSYM platform (Abbott Diagnostic Division) and compared these characteristics to those of the previous version of this assay and to cTnI on the Access 2 immunoassay system (Beckman Coulter, Inc.). Methods: We assayed plasma samples from healthy subjects (n=66) and cardiac patients (n=132) using AxSYM Plus system assays called the old (OLD Ax- SYM) and advanced TnI (ADV AxSYM) methods and using an Access system. Results: An improvement in analytical sensitivity (detection limit) was observed for the advanced cTnI AxSYM compared to the previous method (0.014 vs. 0.31 mg/L), while the cTnI value for the 10% CV (i.e., functional sensitivity) was 0.41 mg/L for the ADV and 1.9 mg/L for the OLD method. The kinetics of cTnI release was similar, as evaluated in 25 patients with typical acute myocardial infarction (AMI). A close linear relationship was found between the two methods on the AxSYM system (OLD cTnI=7.436+6.858 ADV cTnI; R=0.968, n=214) and with the Access system (OLD AxSYM=7.154+7.9 Access, R=0.876, n=158; ADV AxSYM=0.23+1.209 Access, R=0.927, n=160). However, wide bias was found between the OLD and ADV AxSYM methods (mean difference 118.4 mg/L, p0.0001), while more similar results were found between the ADV AxSYM and Access methods (mean difference 2.6 mg/L, corresponding to a mean percentage difference of 17%, p0.0001). In 106 patients with symptomatic rheumatoid arthritis with high rheumatoid factor (RF) concentration, the mean cTnI measured by the ADV AxSYM method was 0.009± 0.031 mg/L (range 0-0.23 mg/L) with a significant correlation (RI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
