Troponins are proteins found in the cardiac and skeletal muscles. When the heart is damaged, it releases troponin into the bloodstream. Doctors measure your troponin levels to detect whether or not you’re experiencing a heart attack. This test can also help doctors find the best treatment sooner.
Previously, doctors used other blood tests to detect a heart attack. This wasn’t effective, however, because the tests weren’t sensitive enough to detect every attack. They also involved substances that weren’t specific enough to the heart muscle. Smaller heart attacks left no trace on blood tests.
Troponin is more sensitive. Measuring cardiac troponin levels in the blood allows doctors to diagnose a heart attack or other heart-related conditions more effectively, and provide immediate treatment.
Troponin proteins are split into three subunits:
- troponin C (TnC)
- troponin T (TnT)
- troponin I (TnI)
In healthy people, troponin levels are low enough to be undetectable. If you’ve experienced chest pain, but troponin levels are still low 12 hours after the chest pain started, the possibility of a heart attack in unlikely.
High levels of troponin are an immediate red flag. The higher the number, the more troponin — specifically troponin T and I — has been released into the bloodstream and the higher the likelihood of heart damage. Troponin levels can elevate within 3-4 hours after the heart has been damaged and can remain high for up to 14 days.
Troponin levels are measured in nanograms per milliliter. Normal levels fall below the 99th percentile in the blood test. If troponin results are above this level, it may be an indication of heart damage or heart attack. However, recent research suggests that women can experience heart damage from a heart attack at levels below the current “normal” cut off. This means that in the future, what’s considered normal may differ for men and women.
Though a rise in troponin levels are often an indication of a heart attack, there are a number of other reasons why levels could elevate.
Other factors that could contribute to high troponin levels include:
- intense exercise
- extensive infection, like sepsis
- myocarditis, an inflammation of the heart muscle
- pericarditis, an inflammation around the sac of the heart
- endocarditis, an infection of the heart valves
- cardiomyopathy, a weakened heart
- heart failure
- kidney disease
- pulmonary embolism, a blood clot in your lungs
- hypothyroidism, an underactive thyroid
- intestinal bleeding
Troponin levels are measured with a standard blood test. A doctor will take a sample of your blood from a vein in your arm or hand. You can expect mild pain and maybe light bleeding.
Your doctor will recommend this test if you’re experiencing chest pain or related heart attack symptoms including:
- pain in the neck, back, arm, or jaw
- intense sweating
- shortness of breath
After taking a blood sample, your doctor will assess your troponin levels to diagnose a heart attack. They’ll also look for any changes on an electrocardiogram (EKG), an electrical tracing of your heart. These tests may be repeated several times over a 24-hour period to look for changes. Using the troponin test too soon can produce a false-negative. Increased levels of troponin can take hours before being detectable.
If your troponin levels are low or normal after experiencing chest pain, you may not have experienced a heart attack. If your levels are detectable or high, the likelihood of heart damage or heart attack is high.
In addition to measuring your troponin levels and monitoring your EKG, your doctor may want to perform other tests to examine your health, including:
- additional blood tests to measure cardiac enzyme levels
- blood tests for other medical conditions
- an echocardiogram, an ultrasound of the heart
- a chest X-ray
- a computed tomography (CT) scan
Troponin is a protein released into your blood after you experience a heart attack. High troponin levels can be indicators for other heart conditions or illnesses, too. Self-diagnosis is never recommended. All chest pain should be evaluated in an emergency room.
If you begin to experience chest pain or suspect you’re having a heart attack, call 911. Heart attacks and other heart conditions can be fatal. Lifestyle changes and treatment can improve heart health and provide you with a higher quality of life. Check out our tips for keeping your heart healthy.