Objective To establish equations for estimating glomerular filtration rate(GFR)based on serum Cystatin C (CysC) and creatinine(Cr) concentration in Chinese adult patients with chronic kidney disease(CKD) Objective To establish equations for estimating glomerular filtration rate (GFR) based on serum Cystatin C (CysC) and creatinine (Cr) concentration in Chinese adult patients with chronic kidney disease (CKD)