Reference ranges for serum cystatin C measurements in Japanese children by using 4 automated assays

Abstract

The data available on reference ranges for cystatin C in children are limited, and there are discrepancies among the available data. The aim of this study was to describe the reference ranges for cystatin C in Japanese children by using 4 automated assays. Serum cystatin C levels were measured in 1128 Japanese children aged 3month to 16years without kidney disease. We calculated age-, gender-, race- and assay-specific cystatin C ranges. For all 4 assays, the median serum cystatin C levels were raised in term infants compared with older children and decreased by the first 2years. The median serum cystatin C levels remained constant throughout up to the age of 14years and decreased in children aged 15-16years. The median serum cystatin C levels in children aged 12-16years were slightly higher in males than in females. Assay-specific differences were also observed in the levels of serum cystatin C measured. Age-, gender-, race- and assay-specific ranges for serum cystatin C should be used as another tool to assess kidney function in children.