CST3 and chronic kidney disease: The currently available formulas for estimating the eGFR include the Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), CKD Epidemiology Collaboration-creatinine (CKD-EPIcr), CKD Epidemiology Collaboration- Cystatin C (CKD-EPICysC), CKD Epidemiology Collaboration-Cys-C - creatinine (CKD-EPIcr-Cys-C) and c-aGFR (a modified abbreviated MDRD equation based on the Chinese CKD patients) equations.