TNNI3 and heart disorder: Taking into consideration the mechanisms of the increase in cardiac troponins, the three groups of the causes for cardiac troponins’ increase can be identified (Table 1): (1) increase in cTnT and cTnI levels associated with myocardial injury in primary cardiac disease, (2) increase in cTnT and cTnI levels associated with myocardial injury in non-cardiac diseases, and (3) increase in cTnT and cTnI levels associated with preanalytical and analytical factors.