Analytical evaluation of two automatic methods to measure blood CK-MB mass and troponin I.

The lack of standardization of methods to measure cardiac markers for coronaria ischaemia, particularly troponin, led us to perform an analytical evaluation of two new immunoassays to quantify CK-MB mass and troponin I using the Dimension RxL automatic analyser. The reliability and analytical intervals of the methods were studied as well as reference values (0.010- 0.228 microg l(-1) for troponin I, 0.20-3.90 microg l(-1) for CK-MB mass) and cuto inverted exclamation mark values (0.77 microg l(-1) for troponin I, 5 microg l(-1) for CK-MB mass) established. The cutoff values were established from 37 patients with acute myocardial infarction and from 20 with unstable angina. The absence of method cross-reactivity was corroborated using myocardial, brain and skeletal muscle tissue. Both methods were highly specific and showed good reliability and practicability in the diagnosis of coronaria ischaemia after 6 h of precordial pain.