Evaluation of 6 cardiac troponin assays in patients with acute coronary syndrome

OBJECTIVE: An increasing body of evidence has demonstrated the value of strategies based on cardiac troponin (cTn) assays in the diagnosis, prognosis and monitoring of patients with acute coronary syndrome (ACS). We evaluated the performance and the practicability of 6 commercially available assays (5 cTnI and 1 cTnT) in patients with ACS.

METHODS: This study was carried out between October 2001 and June 2002 at Armed Forces Hospital in collaboration with Prince Sultan Cardiac Center, Riyadh, Kingdom of Saudi Arabia. Blood samples from 96 patients, 40 with and 56 without clinical evidence of myocardial injury, were used for the evaluation. Cardiac TnI assays were performed using 5 different immunoanalyzers AxSYM (Abbott Laboratories), Stratus CS (Dade Behring), ACS:180 (Bayer), Centaur (Bayer) and Immulite (Diagnostic Products Corporation) while cTnT was measured on the Elecsys (Roche) immunoanalyzer. The sensitivity, specificity and positive and negative predictive values (PV) were calculated for all assays. General and special features related to installation, routine operation, quality control and other various special parameters of each immunoanalyzer were evaluated (using the score of 1-5 for each parameter) and compared with those of other analyzers.

RESULTS: The highest reliability values were observed with Immulite, followed by AxSYM, then Stratus, then ACS:180, and Centaur, and lastly by Elecsys. The highest practicability values were observed with Elecsys, and Centaur, followed by AxSYM and the lowest values were observed with Stratus.

CONCLUSION: Considering the combined performance and practicability score, the difference between the 10% coefficient variation cut off value and the 99th percentile value, and the difference in the relative reactivities to the various cTnI forms, the most favorable values were observed with AxSYM, followed by Immulite and Elecsys, then Centaur and Stratus, and lastly by ACS:180.