Preferred Biomarker of Cardiac Injury
Troponin is a complex of three contractile regulatory proteins, troponin C, T and I, that control the calcium mediated interactions between actin and myosin in cardiac and skeletal muscles.
- Troponin I and T are specific to cardiac muscles, unlike troponin C which is associated with both cardiac and skeletal muscles.
- Troponin C is not used in the diagnosis of myocardial damage.
- Both Troponin I and Troponin T are released into circulation at the time of injury following the same release pattern in the system. However, cardiac Troponin I is slightly more differentiated from skeletal Troponin I than cardiac Troponin T is from skeletal Troponin T.
Cardiac troponins are released into circulation in response to myocardial necrosis. As such, cardiac troponins are the preferred biomarkers for the detection of cardiac injury, and have long assisted physicians in improving diagnostic strategies for the effective management of patients with chest pain.
- Relatively non-specific markers of myocardial damage, such as creatine kinase (CK), creatine kinase-MB (CK-MB), and myoglobin (MYO), were used in diagnostic laboratories prior to the commercial release of the troponin assays.
- Numerous clinical studies on troponin have indicated its superior cardiac specificity in comparison to CK, CK-MB, or MYO.
- Troponin levels remain elevated in the blood longer than CK-MB or MYO, providing an extended diagnostic window for MI.