Clinical Significance

Troponin T (TnT) is a component of the contractile apparatus of the striated musculature. Although the function of TnT is the same in all striated muscles, the cardiac isoform of TnT originating exclusively from the myocardium (cardiac TnT, molecular weight 39.7 kDa) clearly differs from skeletal muscle TnT.

As a result of its high tissue-specificity, cardiac troponin T (cTnT) is a cardio-specific, highly sensitive marker for myocardial damage. Cardiac troponin T increases rapidly (i.e. can be detected within 1 hour of observation time if using high-sensitivity assays) after acute myocardial infarction (AMI) and may persist up to 2 weeks thereafter. In contrast to ST-elevation myocardial infarction (STEMI), the diagnosis of non-ST elevation myocardial infarction (NSTEMI) relies heavily upon elevated cardiac troponin (cTn) concentrations in the appropriate clinical context. The Fourth Universal Definition of Myocardial Infarction (MI) has confirmed cTn as the biomarker of choice.

Diagnosis of MI is made with acute changes in cTn concentrations with at least one serial sample above the 99th percentile upper reference limit (URL), taken together with evidence of myocardial ischemia (symptoms, electrocardiogram (ECG) changes or imaging results). The Fourth Universal Definition of MI recommends as an "optimal precision" the coefficient of variation (CV) of cTn assays at the 99th percentile upper reference limit to be less than 10%.

_{Source: Roche cobas Elecsys Troponin T Gen 5 method sheet, V 3.0 2023-05}