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This calculator calculates the creatinine clearance using the Cockcroft-Gault and MDRD (Modification of Diet in Renal Disease) formula, to approximate the kidney glomerular filtration rate (GFR):
Cockcroft-Gault formula in mg/dl:
![GFRcockcroft = ((140-age) * mass (kg) [ * 0.85 if female ]) / 72 * serum creatinine (mg/dl)](images/formulas/GFR_Cockcroft_mgdl.png "Cockcroft-Gault formula in mg/dl")
Cockcroft-Gault formula in μmol/l:
![GFRcockcroft = ((140-age) * mass (kg) [ * 1.23 if male ] [ * 1.04 if female ]) / serum creatinine (μmol/l)](images/formulas/GFR_Cockcroft_umoll.png "Cockcroft-Gault formula in μmol/l")
MDRD formula in mg/dl:
![GFRmdrd = 186 * serum creatinine (mg/dl)^-1.154 * age^-0.203 [ * 1.210 if african-american ] [ * 0.742 if female ]](images/formulas/GFR_MDRD_mgdl.png "MDRD formula in mg/dl")
MDRD formula in μmol/l:
![GFRmdrd = 32788 * serum creatinine (μmol/l)^-1.154 * age^-0.203 [ * 1.210 if african-american ] [ * 0.742 if female ]](images/formulas/GFR_MDRD_umoll.png "MDRD formula in μmol/l")
The inulin clearance estimates the glomerular function more accurately, since it is fully filtered and neither reabsorbed nor secreted in the tubular system. Note that inulin clearance is not sensitive for early renal disease due to hyperfiltration in the remaining nephrons. After administering inulin, the serum inulin concentration is measured. Urine is analyzed for inulin concentration and measured for volume. Complete urine collection is of crucial importance for the determination of inulin clearance. The inulin clearance slightly overestimates the glomerular function when compared to the MDRD formula.
Inulin clearance formula:
A GFR below 60 ml/min or a rapid decline in GFR indicates possible renal disease.
References:
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine Nephron 1976; 16: 31-41.
- Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group Ann. Intern. Med. 1999; 130: 461-70.
- Pierrat A, Gravier E, Saunders C, Caira MV, Aït-Djafer Z, Legras B, Mallié JP. Predicting GFR in children and adults: a comparison of the Cockcroft-Gault, Schwartz, and modification of diet in renal disease formulas. Kidney Int. 2003; 64: 1425-1436.
- Rahn KH, Heidenreich S, Brückner D. How to assess glomerular function and damage in humans. J Hypertens 1999; 17: 309-317.