Indicator Explainer
Cardiac Troponin (cTnI/cTnT)
Proteins released into blood when heart muscle is injured; the central laboratory marker in suspected heart attack.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Measured in emergency departments with serial sampling (0/1-hour or 0/2-hour protocols) when a heart attack is suspected, and in other settings where myocardial injury is a question — sepsis, pulmonary embolism, chemotherapy follow-up.
Reading results
An elevated value shows myocardial injury, not its mechanism: non-heart-attack causes (sepsis, kidney failure, pulmonary embolism, myocarditis) also raise troponin. High-sensitivity assays have made small elevations common, so interpretation always pairs the trend across serial samples with the ECG and the clinical picture. Reference limits and delta rules differ by assay and laboratory — values from different platforms must not be compared.
Questions to ask a professional
- Which assay and which serial protocol does this laboratory use?
- How do the serial values change, and how do they compare with the assay’s delta rule?
- What non-coronary causes of elevation are relevant to this illness?