Trop T test and Trop I test: the best biomarkers in myocardial infarction

The troponin blood test checks your blood sample for the presence of troponin, indicating if you have had or are at risk of heart damage or a heart attack. The troponin blood test can show up as normal or abnormal, and the results will depend on several factors, including the type of troponin, how long the troponin has been in your bloodstream, and other factors that are unique to you, such as your age and medical histories like heart disease, kidney disease, and lung diseases.

Troponin is a type of protein in the cells of the heart or muscles. They are released by damaged heart muscle cells or skeletal muscle cells due to an injury. That Injury can be decreased blood supply, infection, inflammation, direct trauma to the heart, and increased stress on the heart. Therefore, cardiac troponins are biomarkers of myocardial injury. There are two types of troponins that are used as diagnostic markers. They are troponin I and troponin T. Both of the troponins have the same significance and caveats.

The troponin test is used to screen people who have chest pain or other symptoms of heart disease, but it can also be used to monitor patients with known heart disease to see how they respond to treatment. The main application of troponin is to diagnose a heart attack in people with chest pain.

 

Here’s everything you need to know about the troponin blood test and its uses in diagnosing and treating heart disease. This blog is intended to help the reader understand the role of troponin testing in heart diseases. Understanding how it works can help you know when to ask for it, what it can tell you about your health, and what steps you need to take next.

What is the troponin test?

The troponin test is a simple blood test used to detect damage to your heart muscle. It can be done as a card test or a laboratory test. The doctor may advise either troponin I or troponin T but not both. Here’s everything you need to know about troponins and what they can do for you.

 

What can troponin be tested for?

Troponin is mainly used for the diagnosis and assessment of the prognosis of acute myocardial infarction (heart attack). Troponin levels get elevated in acute myocardial infarction and persist in the blood for 10 to 14 days. But, Troponin elevation is not specific to heart attack, and so it can cause false positives in a variety of situations. For example, troponin is elevated in other skeletal muscles that are damaged, even if those muscles are not cardiac muscles. It’s also elevated when there’s an infection or inflammation anywhere in your body or from certain drugs like statins. This applies to both Trop T and trop I.

What is a normal range of Troponin T or I?

Any value above 0.5 ng/ml is a marker of heart damage, especially heart attack. However, in acute myocardial infarction, levels are elevated several times higher than the actual cut-off of 0.5 ng/ml.

 

Is Troponin a useful test?

The troponin blood test can help you, and your doctor determines if a heart attack or other heart disease may be present.

This test is mainly done on an emergency basis during the evaluation of chest pain. Trop T or trop I helps your doctor determine the cause of your chest pain.

 

Various applications of the troponin test are

Diagnosis of acute MI with Trop T and Trop I

Acute MI results from sudden occlusion of a coronary artery with a clot on top of cholesterol plaque. There is a complete shut-down of blood flow to one portion of the heart. Therefore, the heart is deprived of oxygen and nutrients. This leads to the death of the heart muscle. Death of heart muscles releases troponin T and troponin I into the bloodstream.

 

The diagnosis of a heart attack requires both evidence of the death of the heart muscle (myocyte death) and symptoms or signs of a heart attack. ECG tests and cardiac troponins are the two tests that have immense value in the management of myocardial infarction. The Troponin test checks the blood for markers of myocyte death. ECG test checks for signs of a heart attack.

Cardiac troponin starts rising in the blood two to three hours after a heart attack and so testing for troponins before this may not be helpful. The report can come negative even with a heart attack if done early in the course of a heart attack.   Cardiac troponins stay elevated for 7 to 10 days after a heart attack. So it can diagnose heart attack at 10 days old also. Among two troponins,   levels of troponin T  stay elevated a bit longer than that of troponin I.

An elevated troponin is essential for the diagnosis of a heart attack. Two normal troponins (if appropriately timed) can exclude heart attack in most cases.

However, elevation in troponin levels is not synonymous with diagnosing acute MI. There are several causes for the elevation of troponins. The clinical presentation, along with positive ECG result and troponin result, confirms a heart attack. Your doctor determines the cause of elevated troponin based on your medical history.

Other causes of positive troponin test in patients with chest pain

The most likely diagnosis is a heart attack in patients with classical chest pain or exertional dyspnea, an ECG suggestive of heart attack, and an elevated blood troponin, particularly when markedly elevated. other causes that can present similarly with chest pain and ECG changes where troponin can be elevated are

 

1.             Acute myocarditis

It can clinically mimic a heart attack. Inflammation of the heart muscle is called myocarditis. Viruses are the common culprits for myocarditis. Troponin levels are also elevated, that further confuses your heart specialist. MRI heart is the diagnostic test for myocarditis. A coronary angiogram is often normal.

2.             Takotsubo syndrome (“stress cardiomyopathy”)

Again, these patients are also present clinically in a similar way to myocardial infarction. This is more common in an elderly female. ECG test also shows changes. Troponins are also elevated but only modestly. 2d echo test reveals characteristic findings that are unique to  Takotsubo syndrome. CAG, if done reveals normal coronary arteries

3.             Pulmonary embolism or clots in the lung

clots in the leg (DVT) occasionally detach from there and lodge in the pulmonary artery (which supplies the lungs). This is called pulmonary embolism.

Moderate to severe pulmonary embolism can lead to elevation of cardiac troponins. Elevations are more often modest. They come down to normal within two days, in contrast to the more prolonged elevation with a heart attack(which takes seven days to come down). Mild pulmonary embolism may not raise troponin. CT pulmonary angiogram and d-dimer tests are required to diagnose clots in the lung.

4.             Trauma to the heart

Trauma to the heart can occur during accidents, electric injury, and during CPR done for cardiac arrest. It damages some heart cells. Troponins are released into circulation. Troponin test detects them. These patients also report chest pain due to injury.

Other uses of troponin in heart attack

Troponin can be used to evaluate the degree of damage to the heart by a heart attack. Troponin can also diagnose a second heart attack that can occur within a few days of the first heart attack.

The degree of elevation in troponin levels is also helpful as a prognostic marker. Troponins can be used to diagnose heart attacks that can occur  after noncardiac surgery.

Causes of high troponin levels other than a heart attack or ACS

Troponin is not specific for acute myocardial infarction or acute coronary syndrome. Increased blood concentrations of troponin T or troponin I can also be seen in a variety of other diseases. These diseases are often acute medical problems or serious chronic illnesses.

Most common causes of elevated troponin other than acute myocardial infarction

• Tachycardia – 28 percent
• Pericarditis – 10 percent
• Heart failure – 5 percent
• Strenuous exercise – 10 percent
• No clear precipitating event – 47 percent

Heart-related causes

 

Blunt chest trauma can cause elevated troponins. Implantable cardioverter-defibrillator (ICD) shocks or cardiopulmonary resuscitation (CPR) are a kind of trauma to the heart. They also cause troponin elevation.

High-dose chemotherapy can damage the heart muscle and can lead to a trop T-test positive.

Inflammatory disorders that affect the heart, including acute pericarditis and myocarditis, are other causes of positive troponin test.

 

Heart failure

 

Troponin levels are elevated in various types of heart failure. Congestive heart failure can boost troponin T and troponin T  levels to a mild degree. Troponin elevations tend to be associated with advanced heart failure.

 

Cardioversion

Cardioversion and defibrillation are medical treatments for arrhythmias. Even they can lead to a mild but significant rise in troponin levels.

 

Post-transplant rejection

Post-transplant rejection After heart transplantation can elevate troponin.

Left ventricular hypertrophy or thickened heart wall

Thickened wall of the heart muscle is called Left ventricular hypertrophy. It reduces because of overwork it does in patients with high blood pressure, stenosis of the aorta, or aortic valve stenosis. It can happen in genetic conditions also( hypertrophic cardiomyopathy)

 

Coronary vasospasm

Myocardial ischemia caused by coronary vasospasm (Prinzmetal angina) can elevate troponin.

Atrial fibrillation or Afib

Elevated concentrations of troponin T and I  have been described in patients with atrial fibrillation. Atrial fibrillation is a heart rhythm abnormality where the heart beats irregularly and chaotically at a rapid rate.

Abnormal heart rhythms

Too slow heart rate and too fast heart rate (Tachy- or bradyarrhythmias, or heart block) can sometimes raise troponin levels but only slightly.

 

Aortic dissection

Dissection of the aorta, a surgical emergency, presents with chest pain. Troponin T or Troponin I are elevated. Ct aortogram is the diagnostic test.

Lung disease that causes positive troponin results

 

Troponin elevations are also described in a variety of lung diseases. The right side of the heart supplies blood to the lungs. With lung disease, the right side of the heart takes the stress and can become enlarged and dysfunctional. Serum troponins are elevated in moderate to large pulmonary embolism (clots in the lung).

Serum troponins are elevated even in   pulmonary hypertension, a condition where the pressure in the pulmonary arteries rises.

Acute exacerbation of COPD can also increase troponin levels. Copd is most often caused by long-standing smoking.

 

Critical illness-related causes

Critically ill patients in intensive care units, especially those with diabetes, lung failure, or blood infection, can have raised troponins. These patients are sick and have multiple issues.

Acute brain stroke-related causes

Elevated cardiac troponin levels have been described in the setting of acute brain stroke or bleeding in the brain. An acute brain stroke can cause ECG changes that can mimic myocardial infarction.

Kidney diseases related

Patients with certain kidney problems can have elevated troponin levels. The heart and kidneys are two organs that work together. A disease that affects one organ can affect the organ. Kidney patients will have associated clinical or sub-clinical heart diseases.

Burns related

Severe burns to the body can cause elevated cardiac troponin levels in the blood.

Kawasaki disease-related

Kawasaki disease is an inflammatory disease that affects children. It is associated with elevated cardiac troponin  when underlying myocarditis is present.

Drug toxicity or toxins (i.e., snake venom)

Drugs or toxins that can affect heart muscle rise blood troponin levels.

COVID-19 infection

 Elevated troponin in patients suspected of COVID-19 infection is also very common.

Where do I get my results from the troponin test?

Results are typically available within 24 hours of when your blood was drawn. Your doctor will send them to you in an email. Please print out a copy and bring it with you for your appointment.

 

Who performs the troponin test?

The troponin blood test is performed by medical professionals. Doctors order it when they’re concerned about heart-muscle damage, and it can be performed at any hospital, outpatient facility, or medical lab.

 

How much does the troponin test cost in India?

A troponin blood test typically costs anywhere from 500 rupees to 2000 in Hyderabad, India. Insurance may cover part of that cost—you’ll have to check with your carrier and/or doctor to find out how much.

 

How often should I have a troponin blood test?

The National Heart, Lung, and Blood Institute (NHLBI) recommends a troponin blood test for any person with chest pain or other symptoms of a heart attack. All patients with these symptoms should be tested for troponins as soon as possible after their arrival at the hospital to rule out a heart attack. It is not a kind of test done as a preventive measure or routine health check-up.

 

Where can I get a troponin test?

Troponin tests can be performed in a clinic, diagnostic lab, or a hospital. It is done for patients who have chest pain. As most patients with chest rush to the emergency ward, the majority of troponin tests are done there only.

Does troponin detect blockages in my coronary arteries?

Troponins are a test for heart damage. Heart damage does not occur in all cases of blockages (CAD). Heart attack or MI is one kind of manifestation of coronary artery disease. Troponin is useful only in myocardial infarction.

What should I do if my troponin is elevated?

Your doctor determines the cause of elevation of troponin. If he thinks it is because of a heart attack, he will initiate the treatment immediately. He will likely advise you on a coronary angiogram or stent surgery to the heart.

How to differentiate an old heart attack from an ongoing heart attack?

2d echo test shows rwma in a case of a heart attack. In rwma, a portion of the heart does not contract properly as it should be during a heart scan. RWMA can be seen in both old MI and ongoing MI. Clinical history ( chest pain is present in ongoing MI only ) and troponin test (elevated in ongoing MI only)  are helpful to differentiate them.

How to know if elevated troponin is from a heart attack or other causes?

Medical history is very crucial. Classic symptoms of heart attack point toward MI as the causal factor. ECG test is helpful to some extent. ECG shows characteristic changes during acute MI. The degree of elevation is very high with acute MI. Elevated troponins are detected for several days in case of a heart attack.

For other diseases, elevation is slight or modest and stays shorter for a few days.

I tested trop t-test positive; what is the subsequent treatment?

Treatment depends on the underlying cause. You need an emergency heart stent procedure if it is a heart attack.

Is there any way to do a troponin test at home?

As this test is done for emergency diseases, getting a troponin blood test at home is not recommended. Many diagnostic laboratories provide at-home services. You can do the test at home with a card test.

Is a bedside troponin test possible?

Your healthcare provider can do a troponin card test at the bedside. The result comes within minutes.

Cost of Troponin Kit in Hyderabad, India?

Troponin test kit from Roche is available at Rs 700/-