Cystatin C
This product is used on NEPHSTARTM protein analysis system for quantitative determination of human Cystatin C （Cys C） in serum , plasma
Cystatin C is a small, 13kDa, non-glycosylated basic protein belonging to the cystain super-family of cysteine protease inhibitors. Cystatin C is produced by virtually all nucleated cells, and is present in all investigated body fluids. The production is constant and is unaffected by inflammatory processes, gender, age and muscle mass. It is freely filtered through a normal Glomerular membrane, but is then reabsorbed and almost entirely catabolized in the proximal tubules, no Cystatin C returns to the blood. So, the Cystatin C concentration in human blood is closely related to GFR. Therefore, Cystatin C is considered a useful endogenous marker for the detection of renal impairment, numerous studies have shown that serum Cystatin C is superior to serum creatinine as a marker for GFR.
Particle-enhanced immunonephelometry is applied. This method involves measuring the light scattered by insoluble complexes formed by reaction between specific protein in samples and its respective antibody covalently coupled to latex particles, and the amount of scattered light is directly proportional to the concentration of the protein under condition that antiserum is in excess. The latex particles increase the size of complexes formed and thus the amount of light as well as the test sensitivity. Concentrations are automatically calculated by reference to a calibration curve stored in the instrument.
1. Normal range of Cys C concentration of healthy adult is： for individuals 1-50years:0.55-1.15mg/L, for individuals >50years:0.63-1.44mg/L. We recommend local reference ranges are produced.
2. Diagnosis and treatment can not only depend on determination of Cys C. The clinical symptoms and other laboratory findings of respective patients should be taken into consideration。