<prompt> Which is not a variable of MDRD Modification of Diet in Renal Disease formula?AgeGenderRaceWeight  <response>: TEST : 1. CKD - EPI - cystatin C method BEST ; Cystatin - C is produced by nucleated cells 2. Modification of diet in renal disease formula GFR 186.3 x serum creatinine level mgdl-1.154 x age-0.203 x 0.742 if female x 1.21 if black 3. Cockroft Gault formula 4. Creatinine clearance 5. Inulin clearance 