Subsequent to the publication of the Original Investigation “Time-Updated Changes in Estimated GFR and Proteinuria and Major Adverse Cardiac Events: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study” (Cohen et al, volume 79, issue 1, pages 36-44), which appeared in the January 2022 issue of AJKD, the authors became aware that 4,617 cystatin C values in CRIC required retesting due to poor performance of the laboratory testing platform in use at the time. These cystatin C values had been used to calculate a portion of the estimated glomerular filtration rates (eGFRs) reported in Cohen et al.