Establishment of high-sensitivity cardiac troponin I reference interval for a hospitalized paediatric population under improved selection criteria in the Shandong area

This study aimed to evaluate the distribution of plasma troponin I concentration and establish the 99th percentile reference for hs-cTnI in a hospitalized population without a cardiovascular discharge diagnosis from the Shandong area.The hs-cTnI data of anonymous paediatric patients were collected from Qingdao University-Affiliated Yantai Yuhuangding Hospital from 2016 to 2020. Indirect methods were used to calculate the hs-cTnI 99th percentile reference of the whole population and different age groups. Fitting curves and corresponding equations were displayed to determine the relationship between age and hs-cTnI level using the analysis of covariate variance.Hs-cTnI plasma levels were highest in the first week of life and declined with age in days. This study found significant differences in the troponin reference intervals for children in different age stratification. The serum hs-cTnI concentration decreased with age in days. In some subgroups, hs-cTnI levels between genders showed a significant difference after the analysis of covariance showed that age was the only predictor of hs-cTnI plasma levels. A non-linear relationship was observed between age and hs-cTnI levels. Thus, curvilinear fitting curve equations for each group were constructed to evaluate the possible relationship between age and hs-cTnI concentration.During paediatric period, the highest hs-cTnI concentrations were observed in children aged