Objective To investigate the consistency of different algorithms for establishing the reference range of serum cystatin C(Cys C)by indirect method. Methods Healthy subjects >18 years old who underwent serum Cys C determination at the First Affiliated Hospital of Zhejiang University School of Medicine were enrolled. The 32 266 healthy subjects from January 2019 to December 2023 were used as establishment set,and the 6 531 healthy subjects from January to June 2024 were used as validation set. Harris & Boyd method and the GAMLSS model were used to determine whether to group by gender or age. Six indirect method algorithms, {non-parametric method [the Clinical and Laboratory Standards Institute(CLSI)EP28-NP document],parametric method(CLSI EP28-P document),TMC,refineR,Kosmic and Hoffmann}, were used to establish 95% reference ranges for each group,and the bias ratio (BR) of different algorithms was compared. The reference ranges established by different algorithms were verified. Results The serum Cys C level in males was higher than that in females (P<0.01),and the serum Cys C levels among different age groups were statistically significant (P<0.01). Based on the reference range established by non-parametric method as the reference(the reference range of serum Cys C for males was:0.61-1.01 mg·L-1 for 19-39 years old,0.63-1.10 mg·L-1 for 40-60 years old,and 0.69-1.30 mg·L-1 for≥61 years old;the reference range of serum Cys C for females was:0.50-0.85 mg·L-1 for 19-46 years old,and 0.56-1.05 mg·L-1 for≥47 years old),the reference ranges established by parametric method,refineR and Hoffmann were basically consistent (|BR|≤0.330),while there were significant differences (|BR|≥0.445) with TMC(for males 19-39 years old,and for females overall)and Kosmic(for males overall and 19-39 years old,and for females overall). In the validation set,the pass rates of the reference ranges established by the 6 algorithms for males and females were 90.0%-97.3% and 90.5%-93.0%,respectively. The reference range of serum Cys C was age-related,showing a downward trend starting from 19 years old,gradually increasing for males starting from 40 years old,and gradually increasing for females starting from 47 years old. Conclusions There are certain differences in the reference ranges of serum Cys C established by the 6 indirect method algorithms in Hangzhou. Among them,non-parametric method and refineR algorithms have simpler operations and more stable results. The reference range of serum Cys C for males in Hangzhou is higher than that for females,and it is non-linearly related to age.