Calculation of creatinine clearance from plasma creatinine

Area of Science:

• Nephrology
• Clinical Chemistry
• Biostatistics

Background:

• Glomerular filtration rate (GFR) is a key indicator of kidney function.
• Endogenous creatinine clearance (Ccr) is a common method for assessing GFR.
• Various formulas exist to estimate Ccr from plasma creatinine, but their accuracy varies.

Purpose of the Study:

• To evaluate the effectiveness of four different formulas in estimating creatinine clearance (Ccr).
• To compare the accuracy of these formulas against measured GFR using 51Cr-EDTA clearance and endogenous Ccr.

Main Methods:

• The study included 35 healthy subjects and 41 patients with diminished renal function.
• GFR was measured using 51Cr-EDTA clearance and endogenous Ccr.
• Creatinine clearance was also estimated using four distinct mathematical formulas.

Main Results:

• In healthy subjects, the Cockcroft and Gault and Hull et al. formulas showed higher correlation coefficients with endogenous Ccr compared to Gates and Jellife formulas.
• Across a wide range of GFR values (3.5-145 ml/min) in all subjects, all four formulas demonstrated reasonable correlation.
• The Cockcroft and Gault formula exhibited the best overall performance in estimating Ccr.

Conclusions:

• The Cockcroft and Gault formula is a reliable method for estimating creatinine clearance from plasma creatinine.
• This formula is particularly suitable for use in developing countries with limited resources for GFR assessment.