The test requires both a blood sample and a 24-hour urine sample. The concentration of creatinine in both samples is measured, and the clearance rate is calculated using the formula: Creatinine Clearance (mL/min) = (Urine Creatinine x Urine Volume) / (Plasma Creatinine x Time) This calculation provides an estimate of the glomerular filtration rate (GFR), which reflects the kidney's ability to filter and remove waste products.
