Troponin refers to three different proteins that help regulate the contractions of the heart and skeletal muscles. Normal troponin levels range from 0–0.04 nanograms per milliliter (ng/ml).
The three proteins are troponin C, troponin I, and troponin T. Troponin C binds calcium and transports troponin I so muscles can contract. Troponin T binds troponin proteins to muscle fibers.
The heart releases troponin I and troponin T into the blood following an injury, such as a heart attack. High troponin levels usually mean a person has recently had a heart attack. The medical term for this attack is myocardial infarction.
Keep reading to learn more about normal troponin levels, what to expect during a troponin test, and the treatment options for high troponin levels.
A troponin test measures the levels of troponin in the blood as a way to check for heart damage.
The heart releases troponin into the bloodstream when it sustains damage. Troponin levels in the blood are typically very low, but injuries to the heart can cause them to increase significantly.
Significantly raised troponin levels, particularly those that rise and fall over a series of hours, are a strong indication of a heart injury.
The range for “normal” troponin levels can vary among laboratories, so it is best to discuss the results with the doctor who ordered the test. Laboratories measure troponin in nanograms per milliliter (ng/ml) of blood.
Laboratories may use the following as the normal and at-risk ranges of troponin:
|Normal troponin range
|Probable heart attack
|Above 0.40 ng/ml
Having a result between 0.04 and 0.39 ng/ml often indicates a problem with the heart. However, a very small number of healthy people have higher-than-average levels of troponin. Due to this, if the result is in this range, a doctor may check for other symptoms and order further tests before making a diagnosis.
Many labs in the United States are now using a high-sensitivity version of the troponin test, which the Food and Drug Administration (FDA) approved in 2017. This newer test can detect elevated troponin levels earlier than previous versions.
Doctors usually order a series of troponin tests to monitor how a person’s levels change over time.
During a troponin test, a doctor will take a blood sample from a person’s arm.
After the needle is inserted, a small amount of blood will be collected into a test tube or vial. Some people experience a sting or scratch when the needle goes in or out. This test usually takes less than five minutes.
A person needs to inform the healthcare professional if they feel dizzy or nauseous after giving the sample. Sitting for 5–10 minutes and drinking a glass of water can help relieve this.
A doctor may sometimes request additional blood samples over a few hours.
The most common reason a doctor will test a person’s troponin levels is to see if a heart attack has occurred.
A doctor will not use elevated troponin levels to diagnose a heart condition.
Troponin testing, however, allows a doctor to assess the extent of any heart damage, which can guide treatment decisions and help determine whether current treatments are effective.
Very high levels of troponin typically indicate that a person has had a heart attack, which can occur if the blood supply to some of the heart muscle suddenly becomes blocked.
Troponin levels that are lower but still elevated may point to another diagnosis.
Elevated troponin levels can occur as a result of both cardiac and noncardiac conditions. Possible causes include:
- sepsis, which is a severe and potentially life threatening reaction to an infection entering the bloodstream
- kidney failure or chronic kidney disease
- heart failure
- chemotherapy-related damage to the heart
- pulmonary embolism
- heart infection
- myocarditis, which is inflammation of the heart
- heart damage from using recreational drugs, such as cocaine
- a traumatic injury to the heart, such as from a sudden, hard blow to the chest
Treatment for high troponin levels
High troponin levels are a symptom, not a diagnosis, so treatment will focus on finding and addressing the underlying cause.
Very high levels of troponin usually indicate that a person has recently had a heart attack. The treatment for a heart attack depends on whether the blockage preventing blood flow to the heart is partial or complete.
Some common treatments following a heart attack
- clot-dissolving medications
- coronary angioplasty, which is a procedure that involves threading a small balloon into the coronary artery
- the insertion of a wire mesh tube to prop open a blocked blood vessel during an angioplasty
- bypass surgery, which involves a surgeon creating new pathways for blood to travel through to the heart muscle
A person will likely receive different treatments if their abnormal troponin levels are due to a different cause.
Below are some commonly asked questions about normal troponin levels.
What is considered a high troponin level?
Generally speaking, a reading that exceeds 0.40 nanograms per milliliter (ng/ml) is considered a high troponin level.
What levels of troponin indicate a heart attack?
Very high levels of troponin indicate a heart attack. Exact measurements vary between laboratories but, in general, a troponin level of 0.40 nanograms per milliliter (ng/ml) or more can indicate a heart attack.
If a person has high troponin levels, they should talk with a doctor. This can indicate both cardiac and noncardiac conditions such as heart attack, heart infection, sepsis, and kidney failure.
Can a person have a normal troponin level but have chest pain?
It is possible for a person to have normal troponin levels but have chest pain. In this case, it is likely that their heart has not been damaged.
Can troponin levels go back to normal?
After troponin levels have reached their peak, they will return to normal. Typically, this return to normal troponin levels occurs over
Doctors use troponin tests to assess whether there is damage to a person’s heart.
Generally speaking, a normal troponin level ranges from 0–0.04 ng/ml. However, this can vary among laboratories.
Levels that are higher than 0.04 ng/ml can indicate a recent heart attack or other injuries and conditions that affect the heart.
Usually, doctors order troponin testing if they suspect that a person has had a recent heart attack.
If a heart attack is responsible for the high levels of troponin, treatment may involve emergency procedures to open a blocked artery.
Following a heart attack, troponin levels will return to normal. This usually occurs over