Current status of renal clearances.

Determination of renal clearances continues to have value in clinical situations. Current knowledge of renal function permits expansion of the clearance concept to include non-excretory mechanisms by which kidneys clear substances from blood. Measurement of clearances is useful in quantifying renal function, progression of renal disease, response to therapy, determining the amount of dialysis required. Because accurate chemical methods are clinically cumbersome, isotopic techniques are under development and simple, accurate methods are approaching routine availability.