FaridabadBy Dr B.C. Gupta, MD · 2026-11-01
Cardiac markers are substances released into the blood when heart muscle is damaged. Measuring them helps a doctor tell whether chest pain or breathlessness is coming from the heart, and how much muscle has been affected. The two markers most often discussed are troponin and CK-MB.
Troponin: the preferred marker
Troponin is a protein found inside heart muscle cells, where it helps the muscle contract. When heart muscle is injured, troponin leaks into the bloodstream, and it can be measured with a blood test. Troponin is the preferred cardiac marker because it is highly specific to the heart: damage to other muscles does not raise it in the same way. Levels begin to rise within a few hours of injury, stay raised for several days, and fall gradually. The centre performs both Troponin I and Troponin T.
CK-MB: an older marker
CK-MB is a form of creatine kinase, an enzyme found in muscle. The MB form is concentrated in heart muscle, so it rises when the heart is injured. CK-MB was widely used before troponin testing became standard, and it can still be requested. It rises and falls faster than troponin, which means it is less useful for detecting damage that happened several days earlier. CK-MB can also rise after injury to skeletal muscle, so it is less specific than troponin.
Why timing matters
Cardiac markers do not rise instantly. After heart muscle injury, it takes some hours before troponin becomes detectable, so a test taken very early can be negative even when the heart is affected. For this reason a doctor may repeat the test after a few hours rather than relying on a single sample. Tell the centre when your symptoms started and when they were worst, because that information helps your doctor read the result correctly.
How to prepare
A cardiac marker test uses a blood sample drawn from a vein in the arm. A troponin blood test does not require the patient to fast. Cardiac marker testing is often needed urgently, so the centre can take the sample outside routine hours when requested.
What a result does and does not mean
A raised troponin means heart muscle has been injured, but it does not by itself say why. The cause can be a blocked artery, but it can also be inflammation of the heart, a severe infection, kidney problems, or another strain on the heart. A normal result does not rule out a heart problem either, particularly if the sample was taken very soon after symptoms began. The result is always read together with an ECG, your symptoms and your history, and your doctor is the right person to interpret it.
This article is for general information only and is not medical advice. Always discuss your results and any health concerns with your doctor.
