Troponin

Troponin is a protein of muscle, blood levels of which have become important in diagnosis. "Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.

"Cardiac troponins are regulatory proteins of the thin actin filaments of the cardiac muscle. Troponin T and troponin I are highly sensitive and specific markers of myocardial injury." The level of troponin in the blood of normal individuals may be less than 0.0064 microg/l according to a study of a highly sensitive assay. However, even this cutoff level does not perfectly discriminate normal individuals from patients having acute coronary syndrome.

Troponin levels have become an important diagnostic tool in assessing acute coronary syndrome, but it is dangerous to assume that ACS is the only reason they may be elevated. They supplement, but do not replace, the electrocardiogram, history, and physical examination.

Conditions associated with raised cardiac troponins (analytical causes excluded)

Cardiac diseases and interventions Cardiac amyloidosis Cardiac contusion Cardiac surgery Cardioversion and implantable cardioverter defibrillator shocks Closure of atrial septal defects Coronary vasospasm Dilated cardiomyopathy Heart failure Hypertrophic cardiomyopathy Myocarditis Percutaneous coronary intervention Post cardiac transplantation Radiofrequency ablation Supraventricular tachycardia

Non-cardiac diseases Critically ill patients High dose chemotherapy Primary pulmonary hypertension Pulmonary embolism Renal failure Subarachnoid hemorrhage Scorpion envenoming Sepsis and septic shock Stroke Ultra-endurance exercise (marathon)

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