The serum concentration of Cystatin C is closely related to the glomerular filtration rate (GRF). In renal insufficiency, cirrhosis, tumor and other diseases, it can be a good substitute for serum creatinine, and the creatinine clearance rate becomes a new ideal marker that can reflect (GRF).

The Cys C in the sample and the latex particles of anti-human Cys C antibody in the reagent undergo agglutination reaction, which forms antigen-antibody complex and produces turbidity, which is proportional to the Cys C in the sample when a certain amount of antibody exists. By measuring the absorbance value of specific wavelength, the content of Cys C in serum can be calculated by referring to the calibration curve.