The Vcheck TnI biomarker is an in vitro diagnostic test kit for the in-clinic quantitative measurement of canine Troponin I. The cardiac Troponin I (TnI), is a sensitive and specific circulating marker of cardiac damage in canines. Included in the greater Troponin complex, Troponin I, T, and C, function together as the molecular switch of cardiomyocyte contraction. Cardiac injury leads to the release of cardiac TnI into circulation, where its concentration correlates with the degree of cardiac damage. Heart disease can increase the TnI levels and create ongoing myocardial injury, so frequent monitoring is critical.