Plasma Concentrations of Cardiac Troponin I in Newborn Infants

Ischemia and myocardial necrosis occur in 25–51% of newborn infants with perinatal asphyxia and are often associated with other adverse conditions specific to the neonatal period (1). Biochemical markers are more sensitive and specific than imaging techniques in the diagnosis of myocardial necrosis. Cardiac troponin I (cTnI) has high tissue specificity and sensitivity and is therefore suitable for use in diagnosing even microscopic lesions (2). There is little information about cardiac biochemical markers in newborns, and no reference intervals have been established by the NCCLS standard procedures (3). The European Society of Cardiology and the American College of Cardiology suggest that cTnI and cardiac troponin T (cTnT) concentrations above the 99th percentile in a reference group be used as evidence of myocardial necrosis in adults (2). The present study was carried out to measure cTnI concentrations in plasma from healthy newborns to explore the possibility of a variation in reference values according to gender, age of the newborn, and plasma bilirubin and to suggest an upper limit for the reference interval, which is essential for the interpretation of these measurements in sick infants. We consecutively enrolled 206 apparently healthy infants for whom bilirubin measurements had been requested because of diagnosis …