Research Article

The Performance of Equations That Estimate Glomerular Filtration Rate against Measured Urinary Creatinine Clearance in Critically Ill Patients

Table 1

Renal function estimating equations.

Cockcroft and Gault formula (ml/min)
For males: [(140—age) × actual BW]/sCr × 72
For females: ([(140—age) × actual BW]/sCr × 72) × 0.85
sCr in mg/dL
The equation was calculated three times:
(1) Using actual BW for all patients
(2) Using actual BW for patients with BMI <30 kg/m2 and ideal BW for those with BMI >30 kg/m2
(3) Using actual BW for patients with BMI <30 kg/m2 and adjusted BW for those with BMI >30 kg/m2
Ideal BW
Males: 50 kg + 2.3 kg for each inch above 60 inches of height
Females: 45.5 kg + 2.3 kg for each inch above 60 inches of height
Adjusted BW = ideal BW + [0.4 × (actual BW—ideal BW)]

Modification of diet in renal disease study equations (ml/min/1.73 m2)
Four-variable equation: 175 × sCr −1.154 × age−0.203  × 0.742 (if female)
Six-variable equation: 170 × sCr−0.999 × (Age)−0.176 × (0.762 if patient is female) × (BUN)−0.170× (albumin)0.318
sCr in mg/dL, albumin in g/dL, BUN in mg/dL; to convert BUN from mmol/L to mg/dL, divide by 0.3571

Chronic kidney disease epidemiology collaboration (CKD-EPI) equations (ml/min/1.73 m2)
For females with sCr ≤ 0.7: GFR = 144 × (sCr/0.7)−0.329 × (0.993)age
For females with sCr > 0.7: GFR = 144 × (sCcr/0.7)−1.209 × (0.993)age
For males with sCr ≤ 0.9: eGFR = 141 × (sCr/0.9)−0.411  × (0.993)age
For males with sCr > 0.9: eGFR = 144 × (sCr/0.9)−1.209  × (0.993)age
Age in years and sCr in mg/dL

Jelliffe equation (ml/min/1.73 m2)
For males: (98–16) × (age—20/20)/sCr
For females: [(98–16) × (age—20/20)/sCr] × 0.9
Age in years and sCr in mg/dL

BUN: blood urea nitrogen, BW: body weight, sCr: serum creatinine