Glomerular filtration rate (GFR) is used in the diagnosis of chronic kidney disease (CKD)
1,2 and is an independent predictor of all-cause and cardiovascular mortality and kidney failure in a wide range of populations.
3-6 Clinical guidelines recommend reporting estimated GFR when serum creatinine level is measured
1,2; 84% of US laboratories report estimated GFR.
7 Although the Modification of Diet in Renal Disease (MDRD) Study equation is recommended for estimating GFR,
1,2,8,9 the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) has recently proposed an alternative equation, which applies different coefficients to the same 4 variables used in the MDRD Study equation (age, sex, race, and serum creatinine level).
10 The new CKD-EPI equation estimates measured GFR more accurately than the MDRD Study equation in most,
10-18 but not all
19,20 studies. However; only 4% of US laboratories reporting estimated GFR used the CKD-EPI equation in June 2011; 92% of laboratories still used the MDRD Study equation and 4% used other equations.
7