Gregori Casals1, Xavier Filella, Josep Lluis Bedini. 1. Department of Biochemistry and Molecular Genetics and Core Laboratory (CDB), Hospital Clínic, C/Villaroel, 170, 08036 Barcelona, Catalonia, Spain.
Abstract
OBJECTIVES: We evaluated the analytical and clinical performance of a new ultrasensitive cardiac troponin I assay (cTnI) on the ADVIA Centaur system (TnI-Ultra). DESIGN AND METHODS: The evaluation included the determination of detection limit, within-assay and between-assay variation and comparison with two other non-ultrasensitive methods. Moreover, cTnI was determined in 120 patients with acute chest pain with three methods. To evaluate the ability of the new method to detect MI earlier, it was assayed in 8 MI patients who first tested negative then positive by the other methods. RESULTS: The detection limit was 0.009 microg/L and imprecision was <10% at all concentrations evaluated. In comparison with two other methods, 10% of the anginas diagnosed were recategorized to MI. CONCLUSIONS: The ADVIA Centaur TnI-Ultra assay presented high reproducibility and high sensitivity. The use of the recommended lower cutpoint (0.044 microg/L) implied an increased and earlier identification of MI.
OBJECTIVES: We evaluated the analytical and clinical performance of a new ultrasensitive cardiac troponin I assay (cTnI) on the ADVIA Centaur system (TnI-Ultra). DESIGN AND METHODS: The evaluation included the determination of detection limit, within-assay and between-assay variation and comparison with two other non-ultrasensitive methods. Moreover, cTnI was determined in 120 patients with acute chest pain with three methods. To evaluate the ability of the new method to detect MI earlier, it was assayed in 8 MI patients who first tested negative then positive by the other methods. RESULTS: The detection limit was 0.009 microg/L and imprecision was <10% at all concentrations evaluated. In comparison with two other methods, 10% of the anginas diagnosed were recategorized to MI. CONCLUSIONS: The ADVIA Centaur TnI-Ultra assay presented high reproducibility and high sensitivity. The use of the recommended lower cutpoint (0.044 microg/L) implied an increased and earlier identification of MI.