CST4 and Abnormal renal physiology: Renal dysfunction in combination with another factor. Renal function methods, median (mL/s): GFR-cystatin CKD-EPI 0.72 (0.23-0.94); GFR-creatinine CKD-EPI 0.81 (0.14-1.61); GFR-cystatin-creatinine CKD-EPI 0.77 (0.17-1.5); GFR-MDRD 0.74 (0.14-1.5)