We do not agree with the assertions by Björk et al.1 First, the coefficients for the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation were not modified using results from the external validation. Second, results from the CKD-EPI database have been confirmed in numerous studies2-5 despite variation in serum creatinine assays following standardization.6 Third, the reanalysis of the CKD-EPI data set by Björk et al does not show that the Lund-Malmö-revised (LMR) equation is more accurate than the CKD-EPI equation.