Table 2.

Bias and precision of the MDRD and CG formulasa

Measured GFR (ml/min per 1.73 m2)NMDRD Formula (ml/min per 1.73 m2)CG Formula (ml/min per 1.73 m2)
BiasPrecisionBiasPrecision
≥90482−6.2 (−5.3)18.8 (17.3)−0.3 (0.2)22.7 (21.2)
60–89576−0.8 (−1.1)15.1 (20.4)0.9 (0.9)15.9 (21.4)
30–595970.6 (1.6)9.5 (22.6)2.6 (6.7)10.9 (25.8)
15–293122.3 (11.3)7.2 (35.0)4.9 (24.0)8.0 (38.7)
<151282.4 (26.8)5.1 (54.7)5.2 (54.2)5.3 (58.7)
  • a Results obtained with these formulas were compared with GFR values obtained by measuring the renal clearance of 51Cr EDTA. The study population was divided into five categories according to the GFR levels used to define the five stages of CKD in the K/DOQI CKD classification (5). Bias is defined as the mean difference between estimated and measured GFR. Precision is 1 SD of bias. MDRD, Modification of Diet in Renal Disease; CG, Cockcroft-Gault; CKD, chronic kidney disease; K/DOQI, Kidney Disease Outcomes Quality Initiative