Normal Troponin Values in Pediatric Patients
In healthy children, troponin I levels are generally below 2.0 ng/mL and frequently below the detection limit of 1.5 ng/mL, with no significant difference between children with and without stable congenital or acquired heart disease. 1
Age-Specific Reference Values
- Infants <3 months: The optimal cutoff value is 0.045 ng/mL to differentiate cardiac from non-cardiac diagnoses 2
- Children ≥3 months: The optimal cutoff value is 0.005 ng/mL, which is notably lower than the infant threshold 2
- General pediatric population: Values are typically <2.0 ng/mL in ambulatory patients without acute cardiac disease 1
Clinical Context for Interpretation
The 99th percentile cutoff used in adults (often 0.04-0.1 ng/mL depending on assay) may not be appropriate for pediatric patients, as lower reference values appear more suitable for children. 2
When Troponin is Elevated in Children
- Mild elevations (0.1-2.0 ng/mL): Most commonly associated with myopericarditis, perimyocarditis, drug intoxications, carbon monoxide poisoning, or intensive β-agonist use in acute asthma 3, 4
- Moderate elevations (2.0-8.0 ng/mL): May indicate acute cardiac injury but often associated with recovery if appropriate treatment is initiated 1
- Severe elevations (>8.0 ng/mL): Associated with poor prognosis and high mortality, particularly in critically ill children with systemic illness, trauma, sepsis, or severe pulmonary hypertension 1
Diagnostic Yield in Pediatric Practice
When troponin is measured in previously healthy children presenting with chest pain or cardiac symptoms, elevation (≥0.1 ng/mL) occurs in approximately 9-17% of cases. 2, 3
Predictive Values
- Positive predictive value: 60% for any cardiac diagnosis in unselected patients; increases to 85% when measured in children with cardiac presentations 2
- Negative predictive value: 89% overall; increases to 96% in patients without cardiac presentations 2
Common Pitfalls in Pediatric Troponin Interpretation
Unlike adults where troponin elevation typically indicates acute coronary syndrome requiring urgent catheterization, pediatric troponin elevation most commonly reflects myocarditis or pericarditis (48% of elevated cases), which rarely requires invasive intervention. 3, 4
Serial Testing Considerations
- Serial troponin measurements do not improve predictive values when the initial level is already elevated 2
- However, among children with initially normal levels, 20% develop subsequent elevation, of whom 19% have a cardiac diagnosis 2
- Serial testing at 3-6 hour intervals is warranted when initial troponin is normal but clinical suspicion for cardiac involvement remains high 2
Non-Cardiac Causes in Children
Troponin elevation in pediatric patients frequently occurs without primary cardiac pathology, including:
- Drug intoxications (second most common cause after myopericarditis) 4
- Carbon monoxide poisoning 4
- Intensive β-agonist inhalation therapy for acute asthma 4
- Sepsis and systemic illness 5, 1
- Blunt chest trauma with cardiac contusion (75% of suspected contusions show elevation >2.0 ng/mL) 1
The diagnosis in these cases relies on history, physical examination, ECG, and echocardiography rather than cardiac catheterization, which does not alter prognosis except in rare circumstances. 4