What Is a Cardiac Troponin Test?

Medically Reviewed by Poonam Sachdev on December 18, 2023
13 min read

The cardiac troponin test detects damage to the heart muscle. Troponin is a protein that appears in the blood only when the heart muscle is damaged, as in a heart attack. There are other causes of elevated troponin, but a heart attack is the most common. The earlier test could not measure the low amounts of troponin normally in blood. Troponin T, highly sensitive (hs-TnT) is an advanced marker that is now used for more accurate detection.

Troponin is a protein that’s found inside some of your muscles, including your heart muscle. It plays a critical role in cardiac muscle contraction. In other words, it helps your heart beat.

Normally, only a tiny amount of troponin can be detected in your bloodstream. But that changes if you suffer an injury to your heart muscle. When that happens, some of the troponin is released and begins to circulate in your blood. The greater the damage to your heart, the more troponin gets released.

When you have a heart attack, oxygen-rich blood can’t reach your heart. That causes damage to your heart muscle. That, in turn, causes the release of troponin into your blood.

Three types of troponins exist:

  • Troponin I (TnI) is found only in your heart muscle. Your TnI level will remain higher than normal for 4-7 days after the damage to your heart occurs.

  • Troponin T (TnT) is found in your heart muscle and, in very small amounts, in other muscles. But the structure of the TnT in your heart differs slightly from that found elsewhere in your body. That allows doctors to tell where it comes from and to figure out where the damage has occurred. Your TnT level will remain higher than normal for at least several days, perhaps as long as 3 weeks.

  • Troponin C (TnC) is found in your heart muscle and other muscles.

Only the first two -- TnI and TnT -- can be used to diagnose a heart attack. That’s because there’s no way to tell whether TnC came from your heart muscle or another muscle.

Troponin tests were first used in 1995. They measure the level of troponin in your bloodstream. A higher-than-normal level will tell your doctor that something has damaged your heart muscle. Most often, it’s used in the emergency room when doctors suspect a heart attack.

Along with other tests, a troponin test can help your doctor quickly rule out other possible causes of your symptoms and diagnose a heart attack. If you are having a heart attack, you will undergo more than one troponin test to determine if your troponin level continues to rise. As long as your heart attack remains active, your heart will keep releasing troponin into your bloodstream, and damage to your heart will get worse.

Keep in mind that a higher-than-normal troponin test result means your heart has been damaged, but it cannot tell your doctor what caused the damage.

There are two types of cardiac troponin test:

  • Troponin I (TnI or cTnI) test

  • Troponin T (TnT or cTnT) test

Since their introduction nearly 30 years ago, cardiac troponin tests have become much more sensitive. They are able to detect much smaller amounts of troponin in the bloodstream than previous versions of the tests. This can help doctors diagnose a heart attack or rule it out more quickly.

The test is most often done if your physician suspects you're having a heart attack. If you have chest pain, shortness of breath, and other signs of a heart attack, your physician will ask for a cardiac troponin test.

Symptoms of a heart attack

Chest pain is the most common symptom of a heart attack. It may only be a feeling of discomfort or heaviness, but it also could be severe crushing pain. But some people, especially women, don't experience severe chest pain when having a heart attack. Here are other symptoms that provide clues to what’s happening to you.

  • Pain in other parts of your upper body besides your chest, such as your arms, neck, shoulders, back, jaw, and just above your belly button
  • Shortness of breath
  • Fatigue
  • Sleep difficulties
  • Nausea or discomfort in your stomach similar to heartburn or indigestion
  • Vomiting
  • Heart palpitations, meaning your heartbeat feels like it's racing, pounding, skipping beats, or fluttering
  • Sweating
  • Lightheadedness, dizziness, or losing consciousness
  • Anxiety or feeling a sense of doom

Most people having a heart attack will experience a rise in cardiac troponin levels in blood in 3 hours. Levels remain high for 7-14 days, sometimes longer.

Angina is chest pain that's caused by your heart muscles not getting enough oxygen. If you have had angina for a long time or it gets worse, your physician may ask for a cardiac troponin test.

Creatine kinase is another test that detects heart attacks. But this test is positive in case of muscle injuries anywhere in the body. Cardiac troponins are positive only when the heart muscle is damaged.

Your physician can easily diagnose most heart attacks by the ECG and clinical symptoms. But one type, called NSTEMI (non-ST-elevation myocardial infarction), doesn't show the typical changes on an ECG. A cardiac troponin test tells your physician whether or not you have had a heart attack.

Other uses of high-sensitivity cardiac troponin tests (hs-cTn)

Doctors most often use these tests in the emergency room for a suspected heart attack. But they do have other uses, including:

  • Heart attack long-term outcome. Your doctor may give you an hs-cTn test following your recovery from your heart attack. If your troponin level remains above normal, it means you have a higher risk of having another heart attack or other problem.

  • Unstable angina. Angina is chest pain that develops when your heart does not get enough oxygen-rich blood. The pain comes and goes. Unstable angina is a more dangerous type of angina that puts you at a high risk of getting a heart attack. A high-sensitivity troponin test can help diagnose and monitor unstable angina.

  • Heart failure. Research shows that high-sensitivity troponin tests can help doctors identify people at risk of heart failure even before they have symptoms of the disease. If you have heart failure, the test may be used to see if you're at risk of needing hospitalization for the condition.

  • Pulmonary embolism. This life-threatening condition develops when a clot breaks off from a vein -- often in one of your legs -- and travels to your lungs, where it blocks an artery and cuts off blood flow. An hs-cTn test is more likely to detect this condition than a standard test.

  • Pulmonary arterial hypertension (PAH). High blood pressure in the arteries in your lungs puts strain on your heart and can lead to heart failure. Your doctor may use a troponin test when diagnosing PAH and determining your outlook.

  • Chronic kidney disease (CKD). Kidney disease can cause ongoing damage to your heart muscle. That keeps your troponin level elevated. And because your kidneys don’t work as well as they should, they may not be able to filter troponin out of your blood and into your urine. Tracking your troponin levels may help your doctor determine whether you are at risk of a heart attack or other heart problems.

  • Heart surgery follow-up. Damage to your heart muscle can occur during surgery. You may have an hs-cTn test before and after surgery. This can help your doctor compare the results of the tests and determine if any damage has occurred.

  • People without symptoms. If you're over 65 and have no symptoms of heart disease, regular hs-cTn testing may be useful. An increase of 50% or more in the result predicts heart failure. Your physician can prescribe treatment to help you.

Who needs a troponin test?

Troponin tests have many uses, but it’s most commonly used in the emergency room for people with symptoms of a heart attack.

If you will be having heart surgery, your doctor may measure your troponin level before and after to determine if the surgery caused any damage to your heart.

A troponin test is performed like other blood tests. You don't need to do anything to prepare for it.

A health care professional will draw a blood sample from a vein in your arm. You may feel a small sting when the needle is inserted.

The blood draw normally takes only a few minutes.

The normal levels of troponin in the blood are very low, usually around 0-0.04 nanograms per milliliter. Such low levels are hard to measure accurately with the original troponin test.

The high-sensitivity cardiac troponin (hs-TnT) test can detect low levels of cardiac troponin. If you reach the hospital soon after your symptoms start, this test may give a positive result, while a regular troponin test doesn't.

Diagnosing a heart attack as early as possible is crucial. If your health care provider can detect it early and start treatment quickly, your outcome may be better. Using the hs-TnT test detects heart attacks in 34% more people. 

The detection rate for heart attack by the hs-TnT test is nearly 100% at 3 hours. If your test is negative 3 hours after you first had chest pain and breathlessness, you probably didn't have a heart attack.

What to expect during the cardiac troponin test

A phlebotomist, who specializes in collecting blood samples, or another health care worker will draw a blood sample from a vein, usually in your arm. The sample will then be sent to a lab to be analyzed. Your test results should be available within 1-2 hours.

It’s critical to stop a heart attack as quickly as possible to prevent permanent damage to your heart. For that reason, the health care team will likely play it safe and begin treating you as if you are having a heart attack even before your troponin test results arrive.

You don’t have to do anything to prepare for a troponin test. That’s good because heart attacks are unpredictable and need to be diagnosed and treated right away. But do tell your doctor if you take any dietary supplements. Many of them contain vitamin B7 (also called biotin), which can make your troponin level appear lower than it actually is. That will make it harder for your doctor to diagnose a heart attack.

You will undergo more than one troponin test while you are in the hospital. By comparing the results of your tests, your doctor can tell what’s happening to your heart. If your follow-up test results show no further increases in troponin, your heart attack is likely over and is no longer causing damage. But if your troponin level continues to rise, it means the damage continues to grow. Repeated tests also can give clues about how much damage has occurred.

Related tests

If you have symptoms of a heart attack, you will undergo several tests in addition to the troponin test. These include:

  • Chest x-ray. This provides a picture of your heart and lungs.

  • Electrocardiogram (ECG or EKG). This painless, noninvasive test analyzes your heart’s electrical activity, which controls your heartbeat.

  • Echocardiogram. This painless, noninvasive test uses ultrasound to create a picture of the inside and outside of your heart.

  • Angiogram. This test uses a thin, flexible tube called a catheter, which is inserted into a vein and pushed to your heart. A camera on the catheter takes x-ray pictures to check for any blockages in the arteries that supply your heart with blood.

  • Cardiac computed tomography (CT) scan. This imaging test provides highly detailed three-dimensional x-ray images of your heart from multiple angles.

  • Cardiac magnetic resonance imaging (MRI). Another imaging test, it uses magnetic fields to produce detailed pictures of your heart.

Normal troponin levels

People may have a tiny amount of troponin in their bloodstream even when no damage to the heart has occurred. For that reason, experts have determined what’s considered a normal, or reference, range of troponin. It’s measured in nanograms, which are very small. It takes one billion nanograms to equal a single gram.

As you will see below, high-sensitivity troponin tests use different normal ranges for men (and those assigned male at birth) and women (and those assigned female at birth). Experts are not sure why men and women have different troponin levels. It may be because women and men have different levels of sex hormones. Women have more of the sex hormone estrogen and that seems to offer some protection from heart disease, at least until menopause, when their estrogen level begins to decline.

The ranges are:

  • Troponin I: Less than or equal to 0.04 nanograms per milliliter
  • Troponin T: Less than or equal to 0.01 nanograms per milliliter
  • High-sensitivity troponin I for females: Less than or equal to 15 nanograms per liter
  • High-sensitivity troponin I for males: Less than or equal to 20 nanograms per liter
  • High-sensitivity troponin T for females: Less than or equal to 10 nanograms per liter
  • High-sensitivity troponin T for males: Less than or equal to 15 nanograms per liter

High troponin levels

For high-sensitivity tests, anything above the normal or reference range is considered high and means that your heart muscle has been damaged. But the test can’t tell your doctor what caused that damage. That’s why several other tests must be done to confirm that you are having a heart attack. The troponin test is just one tool to do that.

Apart from heart damage, other conditions that can cause raised levels of cardiac troponin include:

  • Fast heartbeat
  • High pressure in the lung arteries (pulmonary hypertension)
  • Congestive heart failure
  • Inflammation of the heart muscle (viral myocarditis)
  • Blockage of a lung artery by a blood clot (pulmonary embolism)
  • Prolonged exercise (for example, triathlons or marathons)
  • Injury to the heart, as in a car crash
  • Heart surgery
  • Heart muscle disorders such as cardiomyopathy
  • Chronic kidney disease
  • Irregular heart rhythms (arrhythmias) and some of its treatment
  • Stroke
  • Sepsis
  • Exercising too much or too strenuously
  • Extreme emotional strain, such as grief or stress
  • Chemotherapy

The introduction of highly sensitive cardiac troponin tests has improved the treatment of heart disease and other conditions. Your physician can diagnose a heart attack sooner. Early and effective treatment yields better outcomes. Other diseases such as heart failure can also benefit from the cardiac troponin test. When your hs-cTn test values are high, but you don't have symptoms of a heart attack or other condition that deprives your heart of oxygen, your physician will also consider disorders other than heart attack.


Your follow-up will depend on the results of your troponin test and other tests. If your symptoms, troponin test results, and electrocardiogram suggest a heart attack, you will remain in the hospital for further tests to confirm that. Otherwise, you will likely be discharged from the emergency room without further tests. This could take several hours, though. It takes about 2-3 hours for your troponin level to rise after a heart attack begins. If your initial results are normal, your health care team will likely want to test you again in 12 hours to be sure it has not risen before you go home.

Care for a heart attack includes supplemental oxygen to help you breathe, as well as medications and procedures.


  • Aspirin and other blood-thinning medications to reduce blood clots
  • Nitroglycerin to ease chest pain and widen your arteries, improving blood flow to your heart
  • Clot-busting medications
  • Drugs to restore a normal heart rhythm or prevent a dangerous arrhythmia or irregular heartbeat
  • Pain medicine, such as morphine


  • Percutaneous coronary intervention, a nonsurgical procedure to widen a blocked artery and improve blood flow
  • Coronary artery bypass grafting to redirect blood flow so that it goes around a blockage and flows more freely

After your heart attack ends, your troponin level should drop to normal within 4-10 days, though it could take as long as 3 weeks. 

Remember: a high troponin level means your heart muscle has been damaged. The best way to keep your troponin level normal is to lower your risk of heart attack and other heart health problems that cause that damage. You can do that by leading a healthy lifestyle that includes eating a nutritious diet and exercising regularly. Your doctor can best tell you how to reduce risks to your heart.

The troponin test is an important tool that doctors use when they suspect a heart attack. If you believe you are having a heart attack, call 911 right away. The sooner you get diagnosed and treated, the less damaging your heart attack will be and the greater your chances for recovery.

  • What levels of troponin indicate a heart attack?

    Any level above normal indicates that your heart has been damaged. But the test can’t tell whether it was a heart attack or something else that caused the damage. Most often, it’s used in the emergency room to help diagnose someone who may be having a heart attack.

  • What is a normal troponin level?

    It depends on the type of troponin and whether you are male or female, as there are small sex differences in the ranges considered normal. If you are healthy, the amount of troponin in your bloodstream should be extremely tiny.

  • Can troponin levels be high without a heart attack?

    Yes. Other conditions can damage your heart muscle and trigger the release of troponin into your bloodstream. Heart failure, chronic kidney disease, and inflammation or infection of your heart are a few examples of conditions that cause such damage.

  • Can anxiety cause troponin levels to rise?

    Yes. Troponin can go up if you experience extreme stress or other significant emotional strain, such as grief.