CST3 and chronic kidney disease: The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations (one based on creatinine, one based on cystatin C, and one based on both biomarkers) have been shown to be more accurate than the Modification of Diet in Renal Disease (MDRD) equation (which uses creatinine), particularly in persons with GFR >60 ml/min/1.73 m2[4], [5].