What else should I order if my patient's troponin is elevated?

Workup for Elevated Troponin

When troponin is elevated, immediately obtain a 12-lead ECG (if not already done within 10 minutes), perform serial troponin measurements at 3-6 hour intervals to identify rising/falling patterns, order a complete metabolic panel including creatinine and renal function, obtain a chest X-ray, and strongly consider echocardiography to assess for wall motion abnormalities and left ventricular function. 1

Immediate Essential Testing

Electrocardiogram

• Obtain a 12-lead ECG within 10 minutes of presentation if not already performed 1, 2
• Perform serial ECGs at 15-30 minute intervals during the first hour in symptomatic patients with initial nondiagnostic ECG 1
• The ECG determines whether urgent catheterization is needed (ST-elevation or new ischemic changes in contiguous leads indicate need for emergent revascularization) 2
• Consider supplemental leads V7-V9 in patients with initial nondiagnostic ECG at intermediate/high risk for ACS 1
• An ECG obtained during chest pain can be diagnostic, particularly for vasospasm where ST-segment shifts may be reversible 1

Serial Cardiac Biomarkers

• Measure troponin at presentation and repeat at 3-6 hours after symptom onset to identify a rising and/or falling pattern 1
• A single troponin measurement is insufficient—10-15% of patients may not show elevation on initial testing 1
• If initial serial troponins are normal but ECG changes or intermediate/high-risk clinical features persist, obtain additional troponin levels beyond 6 hours 1
• When symptom onset timing is ambiguous, consider time of presentation as time of onset for assessing troponin values 1
• A twofold or higher increase in troponin between measurements implies significantly higher risk of acute myocardial infarction (19-times higher odds for troponin T, 8-times for troponin I) 3
• CK-MB and myoglobin are not useful for diagnosis with contemporary troponin assays 1

Critical Laboratory Studies

Renal Function Assessment

• Measure creatinine and estimate renal function (creatinine clearance) in all patients 1
• Renal dysfunction has negative prognostic impact in patients with elevated troponin and may cause chronic troponin elevation 1, 4
• Elevated troponin in renal failure patients still identifies high risk for ischemic complications 1

Additional Biomarkers

• Consider BNP or NT-proBNP measurement for additional prognostic information and to assess for heart failure 1
• BNP/NT-proBNP should be considered in patients with suspected heart failure 1

Other Laboratory Tests

• Obtain complete blood count to assess for anemia (which can cause supply-demand mismatch) 4
• Check thyroid function if clinical suspicion of thyroid disorder exists 1
• Measure CPK to rule out concurrent myositis, especially in patients treated with combination immune therapies 1

Imaging Studies

Echocardiography

• Obtain resting transthoracic echocardiogram to:
  • Exclude alternative causes of chest pain 1
  • Identify regional wall motion abnormalities suggestive of coronary artery disease 1
  • Measure left ventricular ejection fraction and evaluate diastolic function 1
  • Assess for acute mitral regurgitation or signs of LV dysfunction (which indicate severe underlying CAD and high risk) 1
• When performed during active chest pain, echocardiography provides excellent negative predictive value for acute myocardial ischemia 1

Chest X-Ray

• Obtain chest X-ray to evaluate for pulmonary edema, alternative diagnoses (pulmonary embolism, aortic dissection), and cardiac silhouette 1

Risk Stratification Tools

• Use validated risk scores (TIMI, GRACE) to assess prognosis in patients with NSTE-ACS 1
• Risk-stratification models are useful in guiding management decisions 1

Critical Clinical Context Assessment

Distinguish Acute from Chronic Elevation

• Serial measurements are essential to distinguish acute injury (rising/falling pattern) from chronic stable elevation 4, 3
• Chronic stable troponin elevations occur in conditions like renal dysfunction, heart failure, and chronic cardiac disease 4, 5

Identify Non-ACS Causes

• If clinical presentation is not consistent with acute ischemic heart disease, search for alternative causes of cardiac injury: 1, 4
  • Congestive heart failure
  • Pulmonary embolism
  • Myocarditis
  • Sepsis with systemic inflammatory mediators
  • Tachyarrhythmias (atrial fibrillation, supraventricular tachycardia) 3, 6
  • Takotsubo syndrome
  • Cardiac contusion from trauma
  • Acute respiratory failure or severe hypoxemia

Magnitude Interpretation

• Markedly elevated values (>5-fold upper reference limit) have >90% positive predictive value for acute Type 1 myocardial infarction 4
• Values <2-3 times upper limit in the setting of tachycardia, respiratory distress, or sepsis typically reflect Type 2 injury rather than acute coronary syndrome 4
• The absolute troponin level correlates directly with the amount of myocardial tissue necrosis and risk of death increases proportionately with the level 1, 4

Common Pitfalls to Avoid

• Do not assume any troponin elevation equals myocardial infarction—clinical context (symptoms, ECG changes, serial measurements) must guide interpretation 4
• Do not rely on point-of-care troponin assays, which have substantially lower sensitivity than central laboratory high-sensitivity assays 4
• Do not use a normal troponin on ED presentation (particularly within 6 hours of chest pain onset) to exclude MI—serial testing is necessary 1
• Do not give potent antithrombin and antiplatelet agents to patients with borderline elevated troponin without careful clinical history to ensure myocardial necrosis is from ACS 1
• Remember that troponin is specific for cardiomyocyte necrosis but does not necessarily indicate myocardial ischemia 1, 4