Diagnostic utility of new immunoassays for the cardiac markers cTnI, myoglobin and CK-MB mass
Section snippets
Background
Myoglobin, creatine kinase-MB (CK-MB) and cardiac specific troponins have become the cornerstone for risk stratification and diagnosis of patients with an acute coronary syndrome (ACS) [1]. Since cardiac troponin T (cTnT) or I (cTnI) have demonstrated higher sensitivity than CK-MB, current guidelines recommend the use of troponins rather than CK-MB or myoglobin. This requires high precision troponin assays at values near the decision limit. Therefore, the ESC and the AHA/ACC recommend that the
Patients
We included 85 consecutive patients with ACS, 50 patients after CABG and 50 patients with clinically stable chronic heart failure (HF) NYHA-class III. In patients with an ACS, blood was taken at admission, at average 11.4 h after onset of symptoms (1.3 h–41.7 h; median 10.9 ± 1 h) and the day following admission. In patients after CABG, blood sampling was performed on the first postoperative day and in HF patients during a regular visit in the heart failure clinic. Clinical data were assessed
Results
Baseline characteristics, clinical data and values of the cardiac markers for all patients are shown in Table 1. In patients with an ACS, the definite diagnosis was STEMI in 23 patients, NSTEMI in 40 patients and unstable angina pectoris (UAP) in 22 patients. The values of cardiac markers were elevated in ACS and after CABG but were within the normal range in patients with HF. The highest values were found in ACS and lowest in HF patients with a significant difference of all three cardiac
Discussion
The Elecsys™ (Roche) system for the measurement of cardiac markers troponin T, myoglobin and CK-MB has been in use for several years and has proven its diagnostic utility with high test accuracy. The Innotrac Aio!™ system immunoassays for the determination of cardiac troponin I, myoglobin and CK-MB were introduced recently and have not had extensive clinical use. To date, there are limited data available, which primarily demonstrate the good analytical performance of these new assays [6].
Here,
Conclusion
In this study, we found a close correlation of the values for the biomarkers troponin I, myoglobin and CK-MB assessed by new immunoassays (Innotrac Aio!) as compared to the values obtained with established assays (Roche, Elecsys). However, using the recommended cut-off values, the results by respective assays for cTnT and troponin I were not different, whereas the results obtained by the respective assays for myoglobin and CK-MB were different with regard to patient classification. Therefore,
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