What Is Cardiac Troponin (cTnI / cTnT)?

What it is

Troponin is a regulatory protein complex in cardiac muscle. Cardiac-specific isoforms (troponin I and troponin T) are released into blood when heart muscle is damaged.

Why it matters

Cardiac troponin is the preferred biomarker for diagnosing acute myocardial infarction (heart attack).

Specimen

Whole blood / serum / plasma

Interpretation

Elevation indicates myocardial injury, which is not synonymous with myocardial infarction. Interpretation requires serial testing, the rise/fall pattern, ECG and clinical context.

Limitations

POC qualitative troponin is triage-grade; serial high-sensitivity testing is the standard; rises in non-MI conditions.

Related test: Troponin I Rapid Test — specimen: WB / S / P

Frequently Asked Questions

Is elevated troponin always a heart attack? No — myocardial injury is not synonymous with infarction; other conditions also raise troponin.

Related knowledge

• Cardiac markers hub
• Troponin I vs T