Troponin: Definition, Types, Tests, Uses and Indications

They are a family of proteins found in the skeletal and cardiac muscle fibers that produce muscle contraction.

Troponin tests measure the level of specific cardiac troponin in the blood to help detect cardiac injury.

There are three types of troponin proteins:

  • Troponin C.
  • Troponina T.
  • Troponina I.

Troponin C starts the contraction by binding to calcium and moves troponin I so that the two proteins that shorten the muscle fiber can interact. Troponin T anchors the troponin complex to the muscle fiber structure.

There is little or no difference in troponin C between skeletal muscle and cardiac muscle, but the forms of troponin I and troponin T are different. Measuring the amount of troponin T or specific cardiac troponin I in the blood can help identify people who have suffered heart damage.

Normally, troponin is present in very small undetectable amounts in the blood. When there is damage to the heart muscle cells, troponin is released into the blood. The more damage there is, the greater the concentration in the blood.

Mainly, troponin tests are used to help determine if a person has suffered a heart attack. They can also be useful to evaluate someone looking for other forms of cardiac injury.

When a person has a heart attack, specific cardiac troponin I and T levels may rise in the blood in 3 or 4 hours after the injury and may remain elevated for 10 to 14 days.

How is the sample collected for the test?

A blood sample is taken with a needle from a vein in the arm.

Is any test preparation needed to guarantee the quality of the sample?

Exam preparation is not required.

How is it used?

Troponin tests are ordered primarily to help diagnose a heart attack and rule out other conditions with similar signs and symptoms.

A test of troponin I or troponin T may be performed; usually a laboratory will offer one test or another. The concentrations are different, but basically they provide the same information.

Troponin I and troponin T are proteins found in the heart muscle and released into the blood when there is damage to the heart.

Troponin tests are also sometimes used to evaluate people for heart injuries due to causes other than a heart attack or to distinguish signs and symptoms, such as chest pain, which may be due to other causes.

Tests can also be done to evaluate people with angina if their signs and symptoms get worse. Troponin tests are sometimes ordered along with other cardiac biomarkers, such as CK-MB or myoglobin.

However, troponin is the preferred test for suspected heart attack because it is more specific for cardiac injury than other tests (which may be elevated in the blood with skeletal muscle injury) and remains elevated for a longer period of time .

A test called high sensitivity troponin detects the same protein as the standard test, only at much lower levels.

Because this version of the test is more sensitive, it becomes faster and can help detect heart lesions and acute coronary syndrome before the standard test. The hs-troponin test can also be positive in people with stable angina and even in people without symptoms.

When it rises in these individuals, it indicates an increased risk of future cardiac events, such as heart attacks. Currently, this test is not approved in the USA. UU But the investigation is ongoing and may be available in the near future.

It is already used routinely as a cardiac biomarker in clinical practice in Europe, Canada and other countries.

Indications

Typically, a troponin test will be requested when a person with a suspected heart attack first enters the emergency room, followed by a series of troponin tests performed for several hours.

A heart attack may be suspected and a test performed when a person has signs and symptoms such as those listed below. Keep in mind that not everyone will experience chest pain, and women are more likely than men to have signs and symptoms that are not typical.

  • Pain, discomfort and / or pressure in the chest (the most common).
  • Rapid heart rate, missing a heartbeat.
  • Shortness of breath and / or difficulty in breathing.
  • Fatigue.
  • Nausea and vomiting.
  • Cold sweat.
  • Dizziness.
  • Fatigue.
  • Pain in other places such as the back, arm, jaw, neck or stomach.

In people with stable angina, a troponin test can be ordered when:

  • The symptoms get worse.
  • Symptoms occur when a person is at rest.
  • The symptoms are no longer relieved by the treatment.

All of these are signs that angina is becoming unstable, which increases the risk of a heart attack or other serious heart problem in the near future.

Is there anything else I need to know?

Elevated troponin levels should not be used on their own to diagnose or rule out a heart attack.

Your healthcare provider may also need to see if the troponin levels in a series of tests are high or show an increase over several hours.

Very rarely, people who have a heart attack will have normal troponin levels, and some people with high troponin levels do not have an apparent heart lesion.

What does heart attack mean?

A heart attack means that part of the muscle tissue in your heart is severely injured or has died. The medical term for cardiac muscle death is a myocardial infarction .

Because it is not always possible to determine if there is only one serious injury or if there is a heart attack, the general term for the condition is acute coronary syndrome(ACS).

Most commonly, a heart attack begins with a feeling of pressure or intense pain in the chest, which often extends to the neck or left arm. You may have trouble getting your breath back or you may feel weak and have a cold sweat.

Usually, a heart attack occurs because one of the blood vessels (called coronary arteries) that carry blood to your heart muscle is blocked. This usually occurs when a blood clot forms in a blood vessel that is already partially closed.

Partial closure is usually due to atherosclerosis (often called hardening of the arteries). The obstruction occurs gradually over many years as the lipid plaques deposit along the walls of the blood vessels.

These plaques narrow and harden the arteries and can break unexpectedly, totally blocking the affected artery.