Establishing Reference Intervals for Soluble ST2 Assay in a Korean Population

ABSTRACT

BACKGROUND: Soluble ST2 (sST2) has emerged as a biomarker of heart failure. Previous studies indicated 35 ng/mL of sST2 as the clinically prognostic cut-off value. This study aims to establish reference intervals in a Korean population using an sST2 assay and to evaluate the applicability of the cut-off value. METHODS: From March to May 2014, sST2 levels were assayed in serum samples of 255 cardio-healthy Koreans (128 men and 127 women) using the Presage ST2 ELISA kit (Critical Diagnostics, USA). The reference interval for sST2 was defined using the nonparametric percentile method according to the CLSI EP28-A3c guideline. RESULTS: The median sST2 concentrations were 23.8 ng/mL (interquartile range (IQR), 19.0-28.7), 26.6 ng/mL (IQR, 21.0-30.9), and 21.9 ng/mL (IQR, 17.3-26.5) for the entire cohort, men, and women, respectively. sST2 levels were significantly higher in men than in women (P<0.0001). The 97.5th percentile upper reference limits for sST2 were 43.8 ng/mL, 49.6 ng/mL, and 35.4 ng/mL for the cohort, men, and women, respectively. Gender-specific upper reference limits were similar to limits reported by other studies. CONCLUSIONS: We suggest that gender-specific reference intervals should be used for the Korean population, as application of a single cut-off value of 35 ng/mL may be overcautious of the possibility of false positivity, especially in men.