Creatinine Clearance: A Redundant Clinical Investigation

A substance used to assess GFR by measurement of its renal clearance must be filtered freely at the renal glomerulus, must be neither secreted nor reabsorbed by the renal tubule and must have a constant plasma concentration during the period of measurement. Inulin and 51Cr-EDTA largely fulfil these criteria, I but clearance measurements using these substances involve infusion and are impracticable for general clinical use.