Troponin actually refers to three proteins the body produces that are classed as I, C and T. These are present in cardiac muscles and skeletal muscles, and most times they are at extremely low levels. Troponins present in the heart become medically significant when the levels are raised as this may indicate damage to the heart, especially heart attack. One of the ways that doctors may diagnose whether a heart attack or other heart damage is present is by doing a test to measure these protein levels.
The basic test to uncover potential heart attack or other damage measures troponins T and I (TnT or TnI). They may both be measured, or a single one can be measured. Usually these levels in the healthy person are barely detectable, but when heart damage has occurred, the proteins are released into the blood stream and can be seen in a blood sample. Sometimes when people exercise significantly they might show elevated and detectable levels of TnT or TnI. This doesn’t indicate heart damage.
It’s valuable to use a troponin test when people come to the hospitals with chest pain. Failure to detect TnI or TnT would suggest no heart attack has occurred and the pain is due to other causes. When high levels or troponins are present, myocardial infarction (heart attack) may be a reasonable diagnosis. However, there are other circumstances under which troponin levels might rise, and these could include congestive heart failure, ventricular or supraventricular tachycardia (abnormal hearth rhythms), and cardiomyopathy. When a person has recently had heart surgery or heart transplant, they may also have elevated levels of these proteins. Even procedures like cardiac ablation might result in elevation of TnI or TnT.
There are other reasons why troponin might be high, and they include damage to other parts of the body that can indirectly affect the heart. For instance, people with blood infections may show elevated TnI or TnT levels. Another common reason for their presence is when people have direct exposures to poisons like snake venom. Conditions affecting the lungs like pulmonary embolism or chronic obstructive pulmonary disorder will usually show increased troponin levels. Other potential conditions that may raise troponins include all types of stroke, bleeding in the brain, and certain kinds of organ failure.
With these other conditions, particularly the most serious ones, higher levels of these proteins may indicate greater risk for death. The tests are basically one way of determining how seriously the heart has been affected by illness. In less serious conditions, levels of TnI or TnT can stay elevated for a few weeks and then decline. A return to normal levels may suggest the heart is healing.
