Related Experiment Video
Updated: May 31, 2026
A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice
Published on: May 10, 2013
Comparison of Measured Creatinine Clearance and Clearances Estimated by Cockcroft-Gault and MDRD Formulas in Patients
Sebastião Rodrigues Ferreira-Filho1, Camila Caetano Cardoso, Luiz Augusto Vieira de Castro
1Medical School, Federal University of Uberlândia, Uberlândia MG, Brazil.
Insights
The Cockcroft-Gault (Cl(CG)) formula more accurately estimates creatinine clearance (ClCr(m)) in single-kidney patients than the MDRD formula. This finding is crucial for assessing renal function in individuals with reduced kidney mass.
Area of Science:
- Nephrology
- Renal Physiology
- Clinical Chemistry
Background:
- Estimating glomerular filtration rate (GFR) is vital for managing kidney disease.
- Traditional methods like 24-hour urine creatinine clearance (ClCr(m)) are considered accurate but cumbersome.
- Formulas such as Cockcroft-Gault (Cl(CG)) and Modification of Diet in Renal Disease (GFR(MDRD)) offer estimations but their accuracy in specific populations, like those with a single kidney, is debated.
Purpose of the Study:
- To compare the accuracy of Cl(CG) and GFR(MDRD) formulas against measured 24-hour urine creatinine clearance (ClCr(m)) in patients with a single kidney post-nephrectomy (Nx).
- To determine which estimated formula demonstrates a closer correlation with ClCr(m) in this unique patient group.
Main Methods:
- The study included 36 patients who had undergone nephrectomy (Nx).
- Renal filtration was assessed using three methods: Cl(CG), GFR(MDRD), and measured 24-hour urine creatinine clearance (ClCr(m)).
- Statistical analysis was performed to compare the results and assess correlations.
Main Results:
- Measured ClCr(m) values were significantly higher than those estimated by both Cl(CG) and GFR(MDRD) (P < .001).
- No significant difference was observed between the Cl(CG) and GFR(MDRD) estimated values (P = .72).
- Both estimation formulas showed strong correlations with ClCr(m), but Cl(CG) exhibited a closer association (r²: 0.64) compared to GFR(MDRD) (r²: 0.34; P < .001).
Conclusions:
- In patients with a single remaining kidney after nephrectomy, the Cockcroft-Gault formula provides a more accurate estimation of glomerular filtration rate compared to the MDRD formula.
- The findings suggest that Cl(CG) is a more reliable tool for assessing renal function in this specific population when compared to 24-hour urine collection.
Abstract:
There are doubts about whether the values obtained from the Cockroft-Gault (Cl(CG)) and Modification of Diet in Renal Disease (GFR(MDRD)) formulas are comparable to the more traditional formula used to obtain the creatinine clearance from a 24-hour urine collection (ClCr(m)), particularly in patients with only one kidney. The present study aimed to compare these formulas in individuals with one remaining kidney after previous nephrectomy (Nx) and to verify which estimated formula correlates more closely with ClCr(m). Thirty-six patients who had undergone Nx had their renal filtration analyzed with Cl(CG), GFR(MDRD) and by ClCr(m). The average time after Nx was 11.6 ± 9.0 years, and the average age at the time of the study was 50.7 ± 10.6 years old (X ± SD). The results of three clearances were 81.1 ± 35.6 mL·min·m(2) for ClCr(m), 70.4 ± 24.0 mL·min·m(2) for ClCr(CG), and 71.2 ± 19.2 mL·min·m(2) for GFR(MDRD) (with ClCr(m) > ClCr(CG) and GFR(MDRD); P < .001). No difference was found between the ClCr(CG) and GFR(MDRD) values (P = .72). The data demonstrated that both estimate formulas were strongly correlated with ClCr(m), although ClCr(CG) was more closely associated with ClCr(m) than GFR(MDRD) (ClCr(CG) with r(2) : 0.64 and GFR(MDRD) with r(2) : 0.34; P < .001). In conclusion, for people with only one kidney remaining after NX, our data showed that glomerular filtration rate estimation by ClCr(CG) is more related to the values obtained with the traditional clearance measurement based on a 24-hour urine collection test.
Related Concept Videos
01:25Drug Dosing in Renal Diseases: Measurement of Serum Creatinine Concentration and Clearance
01:28Drug Dosing in Renal Diseases: Estimation of Glomerular Filtration Rate Based on Serum Creatinine Concentration
01:08Renal Drug Clearance: Comparison Between Renal Excretion Methods
Renal clearance is often associated with the renal glomerular filtration rate (GFR), which represents the rate at which plasma is filtered through the glomeruli in the kidney. When drug reabsorption is minimal and there is no active secretion, renal clearance is closely related to the...
01:23Renal Clearance
Renal clearance refers to the volume of plasma cleared of a specific substance, such as creatinine, per unit of time. To measure clearance, urine samples are collected over a 24-hour period during each bladder voiding, followed by a single blood sample at the...
01:17Factors Affecting Renal Clearance: Renal Impairment
One condition associated with renal failure is uremia. Uremia is characterized by impaired glomerular filtration and fluid accumulation in the body. This condition hinders the renal clearance of drugs, resulting in drug accumulation and potential...
01:25Drug Dosing in Renal Diseases: Measurement of Glomerular Filtration Rate