What is the difference between creatinine clearance and GFR?
Creatinine clearance approximates GFR but overestimates it due to the fact that creatinine is secreted by the proximal tubule as well as filtered by the glomerulus. Creatinine clearance can be measured from serum creatinine and creatinine excretion or estimated from serum creatinine using estimating equations. Measurement of creatinine clearance requires collection of a timed urine sample, which is inconvenient and frequently inaccurate. Repeated measurements of creatinine clearance may overcome some of the errors.
