Levey et al. conducted a study involving patients with chronic kidney disease with a mean GFR of 2.39 L/h/1.73 m2 (39.8 mL/min/1.73 m2) and mean Alb levels of 4.0 g/dL and reported that the accuracy of estimating GFR was improved when SCr and the Alb levels were included in the estimation of renal function [28]. Here, ALB is linked to chronic kidney disease.