Featured Article: Levey AS, Coresh J, Greene T, Marsh J, Stevens LA, Kusek JW, Van Lente F, for Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). Expressing the Modification of Diet in Renal Disease Study equation for estimating glomerular filtration rate with standardized serum creatinine values. Clin Chem 2007;53:766–72.3 Chronic kidney disease (CKD4) is now recognized as a global public health problem affecting more than 10% of adults and more than 50% in high-risk subpopulations. Twenty years ago, the rising incidence and prevalence of kidney failure treated by dialysis and transplantation (end-stage renal disease) had been identified as a public health threat, but difficulty in properly relating measured serum creatinine (Scr) values to the level of kidney function had hampered efforts to describe the earlier stages of the disease. The remarkable progress during these 2 decades reflects the strong team work among clinicians, epidemiologists, biostatisticians, laboratory scientists, and in vitro diagnostic (IVD) manufacturers. The 2007 article highlighted here represents a milestone in the development and implementation of equations for estimated glomerular filtration rate (eGFR) for detection, evaluation, and management of CKD. In 1999, the Modification of Diet in Renal Disease (MDRD) Study Group reported a new equation to estimate GFR from serum creatinine (eGFRcr), using more rigorous statistical methods and a more …