The assessment of kidney function using renal clearance of creatinine was originally reported in the early 20th century (Rehberg, 1926) with a method for estimating GFR using endogenous creatinine in 1940 (Steinitz, 1940). Using the concentration of creatinine in urine and serum, as well as the volume of urine collected over a known timeframe, an estimate of GFR can be determined.
For the most accurate estimates of creatinine clearance, urine collections over 24 hours are typically employed; however, ensuring complete urinary collection is fraught with difficulty, limiting the accuracy of these studies. Moreover, plasma clearance of biomarkers is not best estimated using a single timepoint - as such, GFR estimates by creatinine clearance may be falsely increased.
