CK|CK-MB|Troponin|Myoglobin|NT-proBNP|Aspartate aminotransferase|LDH|Electrolytes|Full blood count
What are they?
Cardiac biomarkers are enzymes, proteins and hormones associated with heart function, damage or failure. Some of the tests are specific to the heart, while others are also raised with skeletal muscle damage. Cardiac biomarkers are used for diagnosis and prognosis and are often requested by doctors when someone arrives at A&E with symptoms such as chest pain, pressure, nausea and shortness of breath. These tests are requested, together with other laboratory and non-laboratory tests, to detect heart failure (which is often a chronic, progressive condition that affects the heart’s ability to fill with blood and pump efficiently) and acute coronary syndrome (ACS), and to help determine the prognosis of people who have had a heart attack. ACS is a group of symptoms reflecting a sudden reduction in the amount of blood and oxygen reaching the heart, also called “ischaemia”. This reduction is often due to narrowing of the coronary arteries (atherosclerosis or spasm of the vessels) or unstable plaques, which can cause a blood clot (thrombus) and block blood flow. If the oxygen supply is low, it can cause angina (pain); if blood flow is reduced, it can cause the death of heart cells (called myocardial infarction or heart attack) and can kill the affected heart muscle cells, permanently damaging and scarring the heart.
The aim of cardiac biomarkers is to determine the presence and severity of an acute heart condition as early as possible so that appropriate treatment can be started. Cardiac biomarkers must be available to the doctor 24 hours a day, 7 days a week, with a rapid turnaround.
The biomarkers have different times at which their levels rise, peak and then fall in the body, so they can be used not only to follow the progress of a heart attack but also to estimate when it began and to monitor recovery. They are only some of the cardiac markers used routinely by doctors. Some are no longer used because they are not as specific as the marker of choice, troponin. Many other potential cardiac biomarkers are still being researched, but their clinical usefulness has yet to be established.
Note: cardiac biomarkers are not the same as the tests used to screen healthy people for their risk of developing heart disease. Those can be found under Cardiac risk assessment.
The summary table below shows the main cardiac biomarkers, such as
CK
CK-MB
Myoglobin
Cardiac troponin
LDH
AST
hs-CRP
BNP
It also explains what they are, where they are found, what they indicate, how long they take to rise and return to normal, and the main situations in which they are used.
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