We agree with our European Kidney Function Consortium (EKFC) colleagues regarding the importance of the differing performance between the CKD-EPI equation and that of the EKFC and CKiD U25 equations in the younger age subgroup (18 to 25 years).1,2 At older ages and overall, the performance of all equations is more similar, consistent with our recent paper.3 As seen in Table 1, the lesser performance of the EKFC equation is not substantially improved by use of the recently proposed Q value for US vs.