Your heart releases cardiac enzymes (cardiac biomarkers) when there’s heart damage or stress due to low oxygen. Troponin and creatinine phosphokinase (CPK) levels rise after a heart attack. Elevated heart enzyme levels can also indicate acute coronary syndrome or ischemia. Healthcare providers use enzyme marker tests (blood tests) to measure cardiac enzymes.
When your heart experiences damage or stress due to lack of oxygen, it releases substances called cardiac enzymes into the bloodstream.
Enzymes are proteins that help your body manage metabolism and other chemical processes. Thousands of types of enzymes perform specialized functions, like:
An enzyme marker test is a blood test to measure specific biological markers (biomarkers) in your blood. High (elevated) levels of cardiac enzymes can be a sign of a heart attack or another heart problem. Cardiac enzymes are also called cardiac biomarkers.
Treatments for these conditions vary. An accurate diagnosis is critical to ensuring you receive the appropriate care.
Healthcare providers measure cardiac marker levels to:
A cardiac enzyme marker test requires a blood draw. The blood draw takes just a few minutes. In an emergency situation, the blood draw takes place in the emergency department or hospital. For non-urgent situations, the test may take place at your healthcare provider’s office or a blood-testing lab.
There are different types of cardiac biomarkers. All of them are enzymes or proteins. Elevated heart enzymes may show that you have cardiovascular disease or other heart problems.
Because the heart is the only organ that makes troponin, a biomarker test for this enzyme is the primary test healthcare providers use to detect heart damage from a heart attack or ACS. Troponin levels can rise for up to 12 hours after a heart attack. They stay elevated for up to two weeks. You may get several cardiac enzyme tests spaced several hours or days apart to measure these biomarkers.
Healthcare providers may also test for:
Your healthcare provider may order a cardiac enzyme test if you have symptoms of a possible heart problem. These symptoms include:
Heart enzyme results vary depending on the specific cardiac enzyme and test. The tests measure enzyme levels in nanograms per milliliter (ng/mL).
Most people who don’t have heart damage have troponin levels below 0.02 ng/mL. A higher number can point to severe heart damage.
Troponin and CPK levels can rise for up to 12 hours after heart damage occurs. For this reason, providers often order several cardiac enzyme tests spaced several hours apart.
You may also get one or more of these blood tests:
In addition to lab (blood) tests, you may receive:
A note from Cleveland Clinic
Elevated levels of cardiac enzymes (cardiac biomarkers) in the blood are a sign of heart damage, stress or inflammation. Your heart releases these proteins after a heart attack. Your heart may also release cardiac biomarkers when low oxygen levels cause the heart to work harder than usual. An enzyme marker test (blood test) measures heart enzymes. Healthcare providers use cardiac biomarkers to diagnose, screen and treat heart conditions like acute coronary syndrome, coronary artery disease and atherosclerosis.
Last reviewed by a Cleveland Clinic medical professional on 11/25/2021.
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