Ziegelasch N, et al. - Researchers determined age- and gender-specific cystatin C (CysC) reference values for healthy infants, children, and adolescents and assessed their associations with pubertal stage, height, weight, and body mass index (BMI). Using an immunoassay, they analyzed 6217 fasting, morning venous blood samples from 2803 healthy participants of the LIFE Child study (age 3 months to 18 years) for serum CysC and creatinine levels. At least one follow-up measurement was available in 1636 participants. Percentiles for CysC were calculated. Depending on height and weight, a decrease in median CysC levels was noted over the first 2 years of life, this reduction was from 1.06 to 0.88 mg/l for males and from 1.04 to 0.87 mg/l for females. Stable levels were noted for eight years following the second year of age. An increase of median CysC levels in males to 0.98 mg/l and a decrease in females to 0.86 mg/l was observed from 11 to 14 years of age. They found the association of the change with puberty (ß = 0.105 mg/l/Tanner stage, p < 0.001 in males and ß = − 0.093 mg/l/Tanner stage, p < 0.01 in females) and in males with height (ß = 0.003 mg/l/cm, p < 0.001). Overall, CysC levels depended on age, gender, and height, especially during infancy and puberty. Clinicians were recommended to use age- and gender-specific reference values for CysC serum levels for estimating kidney function.