Profile: First Diagnostic Corp specializes in providing medical devices. Cardiac troponin I have been established as a useful tool in the diagnosis of acute myocardial infarction (AMI). Troponin I is a useful tool in the determination of the source of chest pain. Cell injury from AMI has been shown to result in a level of blood troponin I above the upper limit of normal in approximately 4-6 hours after the onset of chest pain. Maximum concentrations are generally observed after 12-24 hours. Troponin I levels remain elevated for up to 14 days. The use of troponin I is therefore useful as an aid in the diagnosis of AMI given the different release times and half-lives after myocardial infarction.