Establishing reference intervals for high-sensitivity cardiac troponin T in neonates and infants.

Objectives: High-sensitivity cardiac troponin T (hs-cTnT) is used in pediatric healthcare to diagnose and assess the prognosis of various cardiac diseases, such as acute myocarditis, congenital heart disease, dilated cardiomyopathy, and heart failure. However, the standardized age-related reference intervals, 99th percentile cut-offs, and clinical guidelines are currently unavailable, especially in newborns and infants, making interpreting this biomarker challenging.

Methods: Residual serum samples were collected from 1,047 pediatric subjects with no cardiovascular disease, including 145 neonates and 902 infants. The concentrations of hs-cTnT were analyzed using Roche's Elecsys Troponin T hs assay. The age-related 99th percentile cut-offs with 90 % confidence intervals (CIs) of hs-cTnT were established.

Results: Subjects were divided into age subgroups as follows: newborns (0-30 days, n=142), infants aged 1 month (31-60 days, n=223), 2 months (61-90 days, n=152), 3-4 months (91-150 days, n=211), 5-6 months (151-210 days, n=149), and 7 months-1 year (211-365 days, n=149). Serum hs-cTnT concentrations were highest during the first month of life and progressively declined in a year. The 99th percentile cut-offs of hs-cTnT concentration in each group were as follows: 114 (90 % CI: 114-114), 65.6 (63.7-66.1), 55.2 (54.4-55.2), 30.4 (29.1-30.9), 23.5 (22.1-23.5), 12.7 (12.4-12.7) ng/L. The 97.5th percentile cut-offs for each group were 109.4 (105.2-114), 62.5 (60.5-63.9), 52.3 (50.3-54.4), 29 (28.5-29.1), 20.5 (19.2-23.4), and 12 (12-12.1) ng/L.

Conclusions: This study aimed to provide reliable pediatric reference values for hs-cTnT based on a population of well-child children. These reference intervals and 99th percentile cut-offs will inform clinical decisions in the pediatric cardiology setting.