Troponins are part of a group of proteins that regulate heart contraction. Troponin T is released into the blood when there is heart damage. Its measurement in blood is particularly useful in diagnosing acute myocardial infarction. Troponin T develops between 2 and 4 hours following the symptoms of an infarction. The maximum concentration is reached after 12 to 18 hours and the level remains high for 5 to 14 days after the infarction. This test can also be used to assess heart problems other than an infarction, such as cases of angina. An increase in troponin T in angina cases may be indicative of a high risk of more severe heart problems. This test has a high sensitivity (hs) and therefore can be used to measure a very slight increase in the blood, allowing heart problems to be detected very early, almost as soon as they occur. Note that an isolated hs troponin T result is not sufficient to diagnose or rule out a heart problem. A more comprehensive clinical assessment is required. Also, an infarction can occur without an increase in troponin T and, conversely, an increase can be observed without any apparent heart problems.