Distribution of ECV/wt by age (in the 788 person-visits) and Tanner stage(in the 756 person-visits) from the CKiD cohort visits 1 and 2. The median values of ECV/wt across categories of age (from left to right) were 0.26, 0.24, 0.23, and 0.21 L/kg and across categories of Tanner stage (from left to right) were 0.24, 0.23, 0.23, 0.22, and 0.20 L/kg.