What is the MDRD Study equation?
The 4-variable MDRD Study equation was developed in 1999 using data from 1,628 patients with CKD with GFR from approximately 5 to 90 milliliters per minute per 1.73 m2. It estimates GFR adjusted for body surface area3, 4 and is more accurate than measured creatinine clearance from 24-hour urine collections or estimated by the Cockcroft and Gault formula.3, 4 The equation is: GFR = 186 x (SCr)-1.154 x (age)-0.203 x (0.742 if female) x (1.210 if African American) The equation was re-expressed in 2005 for use with a standardized serum creatinine assay, which yields 5 percent lower values for serum creatinine concentration 5, 6: GFR = 175 x (Standardized SCr)-1.154 x (age)-0.203 x (0.742 if female) x (1.210 if African American) GFR is expressed in mL/min/1.73 m2, SCr is serum creatinine expressed in mg/dL, and age is expressed in years. In the MDRD Study, the equation has an R2 value of 89.2%, with 91% and 98% of the estimated values falling within 30% and 50% of measured values, respectiv
