How to Maintain Normal Troponin Levels

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.

What Is a Cardiac Troponin Test?

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 test now in use.

What Is Troponin?

Troponins are proteins needed for the contraction of cardiac muscles and skeletal muscles. Skeletal muscles are the muscles that move our limbs and other parts that we control. Cardiac muscle forms the wall of the heart, and is the part most damaged in a heart attack.

Three types of troponin are known — troponin C, troponin I, and troponin T. All three types are present in cardiac and skeletal muscles. The troponin I and troponin T in cardiac and skeletal muscles are different from each other. The tests we use can measure the cardiac types of these proteins particularly. The troponin C of both cardiac and skeletal muscles is identical. Laboratories don’t measure this protein.

The two types of cardiac troponin measured by tests are troponin T (TnT) and troponin I (TnI). Both are good markers of heart injury.

What Is a Cardiac Troponin Test?

This test measures the level of troponin in the blood. When the heart is well, troponin is in the heart muscle cells and does not reach the blood. Only when the heart is damaged does troponin appear in the blood.

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If a heart artery is blocked, the muscle cells are damaged because of a lack of oxygen. Troponin appears in the blood. The more the damage to the heart muscle, the higher the level of troponin in the blood.

Cardiac Troponin Test — Why Is it Done?

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. Along with this, they may also ask for an electrocardiogram (ECG or EKG) and other blood tests like myoglobin or CPK isoenzymes.

Most people with a heart attack will have a rise in blood levels of cardiac troponin in 3 hours. Levels remain high for 7 to 14 days.

Angina is a chest pain. It is 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 a test that also detects heart attacks. But this test is also positive with muscle injuries anywhere in the body. Cardiac troponins are only positive 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.

High-Sensitivity Cardiac Troponin (hs-TnT)

The normal levels of troponin in the blood are very low. Usual results are 0 to 0.04 nanograms per milliliter. Such low levels are difficult to measure accurately with standard testing.

The troponin T highly sensitive (hs-Tnt) test was developed for more precise measurement. A genetically re-engineered detection antibody is used. This reduces the interference by heterophilic antibodies. The normal range of cardiac troponin by this test is 0 to 14 nanograms per liter.

The normal range is different for women and men. A value of 10 nanograms per liter is considered the upper limit of normal for women. For men, 15 nanograms per liter is considered the cut-off value. Results above these levels in people with chest symptoms show that a heart attack has happened.

The hs-TnT allows the detection of low levels of cardiac troponin. This is very important if you reach the hospital soon after your symptoms start. This test may give a positive result when a regular test doesn’t.

The early diagnosis of myocardial infarction (heart attack) is crucial. If your physician can detect it early and start treatment quickly, the outcome is better. Using the hs-TnT detects 34% more people with myocardial infarction.

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

High-Sensitivity Cardiac Troponin (hs-TnT) — Other Uses

Heart attack long-term outcome. People who have raised levels of hs-TnT seven weeks after the heart attack were at higher risk of further heart events.

Heart failure. Only 10% of people with heart failure have a positive cardiac troponin test result. The highly-sensitive TnT test detected 92% of these people.

The hs-TnT can predict outcomes. People with heart failure and the low levels of cardiac troponin had a 7.8% death risk in 2 years. Those with the highest levels had a 35.6% mortality.

Pulmonary embolism. This life-threatening condition is caused by a clot detaching from a vein and traveling to the lung arteries. A hs-TnT test is more likely to detect this condition compared to a standard test.

Pulmonary arterial hypertension. An increase in the blood pressure in the pulmonary arteries, leading to strain on the heart and heart failure. Raised hs-TnT is useful for diagnosing pulmonary arterial hypertension. It can also predict future mortality.

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

Other Causes of Elevated Troponin

Apart from heart damage, some other conditions also cause raised levels of cardiac troponin:

• 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 like cardiomyopathy
• Chronic kidney disease

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 like heart failure can also benefit from the cardiac troponin test. When your hs-TnT test values are high, but you don’t have symptoms of cardiac ischemia, your physician will also consider disorders other than heart attack.

Show Sources

SOURCES:
American College of Cardiology: “High-Sensitivity Cardiac Troponin in the Evaluation of Possible AMI.”
Journal of Geriatric Cardiology: “High-sensitive cardiac troponin T.”
Mount Sinai Hospital: “Troponin test.”
Ramrakha, P. Oxford Handbook of Acute Medicine, Oxford University Press, 2019.

How to Maintain Normal Troponin Levels

Healthy adults — those with no recent history of heart damage, kidney disease or serious lung damage — normally do not have high enough levels of the protein called troponin in their bloodstreams to be detected. However, when someone has a heart attack or experiences another injury to the muscles of the heart, troponin levels quickly rise.

Doctors can now measure troponin levels in the blood within hours of symptoms emerging in order to screen for life-threatening problems. Troponin tests are more sensitive and fast-acting than tests used in the past to detect heart attacks, which means patients at risk for cardiac arrest and myocarditis (inflammation and damage of the heart muscle) can receive medical attention right away that sometimes can be life-saving.

What Is Troponin?

Troponins describe a group of proteins that are normally only found in the skeletal muscles and heart but can leak into the bloodstream if the heart becomes damaged.

These proteins help regulate muscle contractions and functions of skeletal and heart (cardiac) muscle fibers. They are released into the blood when the cells of the heart are injured and not getting enough oxygen and nutrients.

The more severely damaged the muscles of the heart are, the more that is leaked into the blood.

According to the National Institutes of Health, sometimes troponin is called other names, such as:

• cardiac troponin I (cTnI)
• cTnT
• cTN
• and others

Most heart disease tests focus on three main types of troponin proteins: troponin C, T and I. The role of troponin C is to initiate contractions by binding calcium and working together with troponin I to pull muscle fibers shorter.

Troponin T binds this protein to a larger muscle fiber complex.

Normal Troponin Levels

Levels of troponin in the blood are measured to determine whether the heart is damaged and if a heart attack (acute myocardial infarction) has occurred.

What is a normal troponin level?

Results are given in measurements of nanograms per milliliter (ng/mL). The normal range is between 0 and 0.4 ng/mL.

What is an elevated troponin level?

High levels of troponin in the blood can indicate that someone has recently had a heart attack, which describes when blood flow to the heart muscle is cut off, causing tissue damage.

High levels can also explain why someone may have chest pains, also called angina, which is a risk factor for a heart attack. If someone reports chest pains and his or her troponin level in the blood is detected to be rising, this can alert the patient’s health care provider that a medical intervention is needed right away.

Anything above the normal range (0 and 0.4 ng/mL) is considered to be an elevated troponin level in the blood. However, the higher the level is, the more likely it is that a heart attack occurred.

What level indicates a heart attack? A measurement close to 0.4 may not necessarily mean one has occurred, but a measurement such as 10 or more is a very good indication that one has.

What does a low troponin level mean?

Normally levels are very low in the blood — so low, in fact, that they cannot be detected. Low levels are therefore not a concern.

Causes of Elevated Troponin

Elevated troponin causes can include:

• Having recently had a heart attack (myocardial infarction or death of cardiac muscle), which usually results in the highest levels in the blood compared to other health problems — this may be due to congestive heart failure/acute coronary syndrome (ACS) or coronary heart disease
• Kidney disease/renal failure
• Blood clot in the lungs/pulmonary embolism
• Severe infection, such as sepsis
• Atrial fibrillation
• Myocarditis
• Myocardial contusion
• Pericarditis, inflammation around the sac of the heart
• Endocarditis, infection of the heart valves
• Intense exercise, which is only temporary and not generally harmful

How to Treat High Levels

If only a small amount of troponin is found in the blood, this usually means there is some damage to the heart, but it’s likely caused by a health problem other than a heart attack/cardiac arrest if it doesn’t rise and quickly decreases. In this case, treatment may not be necessary, although it depends on the individual.

In order to reduce troponin levels, it’s necessary to treat the underlying cause of the elevated levels. It’s also recommended to take steps to generally improve cardiovascular health, including by reducing high blood pressure or high cholesterol.

Some research shows that taking statins can reduce high levels. One study published in the journal Circulation found that those with high troponin levels who took statins experienced a fivefold lower risk of heart attack or death from coronary heart disease compared with those whose troponin levels were unchanged or increased.

Statins are used to prevent coronary heart disease in people who are considered high-risk for cardiac arrest. The researchers involved in the study mentioned above explain, “A decrease in troponin could indicate treatment is effective, whereas any increases in blood troponin could prompt a change in treatment strategy.”

Depending on what other tests reveal, other medications and treatments may be necessary. These can include:

• medications to prevent clots and control other risk factors
• insertion of a stent to open a blocked blood vessel
• coronary angioplasty to open up a blockage
• bypass surgery to help blood reach the heart
• ablation to remove damaged cells

What Happens During a Test

The Food and Drug Administration (FDA) approved the use of high-sensitivity troponin tests in the United States in 2017. These tests are used to detect heart injury and acute coronary syndromes as quickly as possible.

Levels of cardiac-specific troponins I and T tend to be elevated in the blood within three to six hours after injury to the heart. It takes a few hours for levels to rise after heart cell death begins, so tests are usually repeated.

Once elevated above normal levels, troponin may remain high for 10 to 14 days if a heart attack has occurred.

What is the function of troponin I? Cardiac troponin I and T are biomarkers of cardiac injury, so they are usually included in tests following a suspected heart attack.

Normally either troponin I or T levels are tested but not usually both, since levels of each provide the same information. Sometimes doctors will also use other biomarkers to confirm suspected damage to the heart, such as by testing CK–MB or myoglobin.

A troponin test involves taking a blood sample from a vein in the arm.

When should troponin levels be taken? They are usually tested several times over the course of about 24 hours to monitor how they are changing.

Most often someone’s levels will be tested if they report experiencing symptoms of a heart attack or chest pains. Symptoms that can lead to tests being ordered include:

• Chest pains (angina) and discomfort
• Trouble breathing
• Pain in the arms (usually one), back, jaw or neck
• Nausea and sometimes vomiting
• Fatigue
• Dizziness
• Increased sweating

Doctors usually interpret troponin levels by monitoring how they drop after someone reports chest pains and other symptoms. If levels decrease within 12 hours of symptoms starting, there’s a good chance the symptoms were not caused by a heart attack.

If they stay elevated for several days or more, the person likely did experience one.

Other tests will also be used to make a diagnosis, such as other cardiac tests, a physical exam, clinical history and ECG.

Conclusion

• Troponins describe a group of proteins that are normally found in the skeletal muscle and heart. Normal troponin levels in the blood are very low, but levels can increase due to heart damage, a heart attack (myocardial infarction) or other serious illnesses.
• What is considered a high level? The normal range is between 0 and 0.4 ng/mL. Anything above this is considered high and potentially problematic. The higher the level, the more serious the condition is.
• Treatment for high troponin levels involves resolving the underlying health problem that’s causing levels to rise (heart disease, infection, etc.). Improving heart health and sometimes taking statins may also be recommended.