By introducing cystatin-C in the CKD-EPI formula we obtained a cumulative 15.8% and 17.4% increase in the percentage of patients with eGFR below 50 ml/min/1.73 m2 as compared to CKD-EPICr and MDRD, respectively, while, by comparing BIS1 and BIS2 formulas, the mismatch was almost halved (7.7%). This evidence concerns the gene CST3 and chronic kidney disease.