Troponin Testing

Causes of Elevated Troponins

• Cardiac Causes

  • ACS (including unstable angina that may not always show elevation, but NSTEMI does)

  • Myocarditis or pericarditis

  • Heart failure and cardiomyopathies

  • Significant arrhythmias (sustained tachyarrhythmias)

  • Cardiac procedures or trauma (including electrical cardioversion or ablation)

• Non-Cardiac Causes

  • Pulmonary embolism (right ventricular strain)

  • Sepsis, especially if hypotension or septic shock

  • Renal failure with reduced clearance

  • Severe burns, especially >30% total body surface area

  • Extreme physical exertion (intense endurance events)

  • Critical illnesses (severe anaemia, prolonged hypotension)

When to Order Troponins in General Practice

• Reasonable if >24 hours since symptom onset and the patient is low-risk (chest pain fully resolved, normal observations, no new ECG changes)

• Avoid if patient has any high-risk features:

  • Heart failure signs or syncope

  • Abnormal ECG (ST/T changes, new bundle branch block)

  • Chest pain suggestive of ongoing or unstable ACS

• High-risk patients should be referred promptly to the ED for urgent assessment and serial troponin testing rather than a single outpatient measurement

Troponin Kinetics

• Rise: Begins 3–4 hours after myocardial injury

• Peak: Usually at 24–48 hours

• Duration: Can remain elevated up to 2 weeks

• High-Sensitivity Troponin (Hs-Tn) allows earlier detection of myocardial injury, but can be elevated in stable conditions (CKD, chronic cardiac disease), emphasising the need for clinical correlation

Notes:

• Dynamic Changes

  • Serial troponin measurements (e.g., baseline and repeat 3 hours later) confirm a rising or falling pattern consistent with acute myocardial injury

  • A single borderline value may be inconclusive without a second measurement

• Non-Ischaemic Causes

  • Often produce a persistent but relatively stable troponin elevation rather than the dynamic pattern seen in type 1 MI

• Interpretation

  • Elevated troponin alone does not confirm ACS, but in the right clinical context (symptoms, ECG findings), it strongly suggests myocardial infarction

  • Unstable angina can occur with normal troponins, so persistent suspicion warrants referral or further investigation

• Practical Points for GPs

  • Be aware of conditions such as renal insufficiency or heart failure that can cause chronic mild troponin elevation

  • If in doubt, discuss with cardiology or emergency services to avoid delayed treatment

  • Advise patients to seek urgent review if symptoms recur, given potential for progression to complete occlusion or infarction