Analytical performances of a new rapid assay of soluble ST2 for cardiac and inflammatory diseases and establishment of the reference intervals for children and adolescence in China.

Background: sST2 has emerged as a potential disease biomarker of cardiac and inflammatory diseases in pediatrics. This study aimed to evaluate the performance of the new Pylon sST2 assay and establish the reference intervals of sST2 in children and adolescence in China. Methods: The experiments on precision, linearity, effects of interferents and sample stability were carried out to evaluate the analytical performances. A total of 240 healthy participants, aged from 2 to 17 years were enrolled. The nonparametric method was used to calculate the age- and sex-specified reference intervals. sST2 levels were measured in children with different diseases to evaluate the assay's diagnostic performance. Results: The repeatability and within-laboratory imprecision CVs of the assay were 6.0% and 7.6% at 19.5 ng/ml, and 3.1% and 5.9% at 289.8 ng/ml, respectively. The method showed linearity between 2.5 and 918.5 ng/ml. It was also noteworthy that the sST2 level was not affected in the presence of hemoglobin (2 mg/ml), triglyceride (30 mg/ml), bilirubin (0.3 mg/ml) and cholesterol (5 mg/ml). sST2 was found stable for 5 days at 4 °C in serum sample. The reference interval was determined as 2.1-21.0 ng/ml in general. No significant variation was observed by sex. However, sST2 increased constantly with age, especially in male. Increased sST2 was found in patients of systemic lupus erythematosus, sepsis, Crohn's diseases, respiratory failure and post cardiac surgery. Conclusions: The Pylon sST2 assay showed good analytical performances. The reference intervals were established in children and adolescence and sST2 showed potential clinical values in several diseases in pediatrics.