Difference against mean of measured GFR (⁵¹Cr-EDTA) and estimated GFR (A: Cockcroft-Gault [CG] formula, B: MDRD equation) in 156 microalbuminuric (•) and 227 macroalbuminuric (○) type 2 diabetic patients. The mean difference between the methods (the bias) in microalbuminuric patients was an underestimation of 14 ml · min⁻¹ per 1.73 m²(95% limits of agreement −58.7 to 30.7) for the Cockcroft-Gault formula and an underestimation of 23 ml · min⁻¹ per 1.73 m² (−66.1 to 20.3) for the MDRD equation compared with measured GFR. In patients with nephropathy, for the Cockcroft-Gault formula there was an underestimation of 3 ml · min⁻¹ per 1.73 m² (−39 to 33) and for the MDRD equation there was an underestimation of 11 ml · min⁻¹ per 1.73 m² (−47 to 25).