What is a troponin test?

A troponin test looks for the protein troponin (there are two forms related to your heart, troponin I and troponin T) in your blood. Normally, troponin stays inside your heart muscle’s cells, but damage to those cells — like the kind of damage from a heart attack — causes troponin to leak into your blood. Higher levels of troponin in your blood also mean more heart damage, which can help healthcare providers determine the severity of a heart attack.

Newer versions of this test are much more sensitive and can pick up far smaller amounts of this protein in your blood than before. That can speed up the process of diagnosing a heart attack. This test is also useful when other tests are inconclusive or when you have vague symptoms. This test is also known as a cardiac troponin test, or uses the abbreviations cTn, cTnI or cTnT, depending on the specific type of test. Some versions of this test can only detect one type of troponin, while others can detect both.

What is troponin?

Troponin is a protein, a complex chemical molecule, found in certain types of muscle in your body. Under normal circumstances, it exists inside muscle cells and only freely circulates in your bloodstream in tiny amounts. However, damage to certain types of muscle cells can cause more troponin to escape into your blood.

There are two types of troponin that are more detectable after heart muscle damage, which use the letters I and T to tell them apart.

  • Troponin I (cTnI). This kind of troponin is unique to heart muscle.
  • Troponin T (cTnT). Troponin T does exist in other types of muscle, but the amounts are very limited. The Troponin T in your heart muscle also has a slightly different structure, which doesn’t occur anywhere else in your body.

Troponin levels usually increase sharply within three to 12 hours after a heart attack and peak about 24 hours after the heart attack. They will also remain high for several days.

Why would I need this test?

The most common use of troponin tests is to confirm or rule out a heart attack. However, any kind of damage to heart muscle can potentially cause the release of this chemical into your bloodstream. Other conditions that can cause your troponin levels to increase include:

  • Chronic kidney disease.
  • Pulmonary embolism (a blood clot in your lungs).
  • Congestive heart failure.
  • Heart surgery.
  • Heart valve diseases.
  • Irregular heart rhythms (arrhythmias).
  • Sepsis.
  • Exercising too much or too strenuously.
  • Extreme emotional strain, such as grief or stress.
When and where is this test performed?

This test sees most of its use in hospital emergency rooms when medical professionals suspect a recent heart attack. However, if you’re already a patient in the hospital and doctors need to check for heart damage for any reason, this test might also provide useful information.


How does a troponin test work?

This test involves taking a sample of your blood, analyzing it and determining if there’s any troponin in the sample. If the troponin level is high enough, it’s a clear indicator of heart damage. This test, combined with other diagnostic tests and methods, is a key tool to diagnose a heart attack.

Repeating this test is common because comparing your troponin levels over time can help providers determine the extent of the heart damage and the likely prognosis for your case. Troponin is also useful even days after a heart attack because troponin I levels will remain high for at least five to seven days after a heart attack. Troponin T levels last even longer and will remain high for up to three weeks after a heart attack.

Newer, high-sensitivity tests can often detect even the tiny amounts of troponin in your blood that happen normally. In these cases, providers will repeat the test. If they see an increase in the troponin level on the repeat test, that’s an indication of heart muscle damage.