Measurement of renal clearance of inulin and PAH in the steady state without urine collection.

Two different methods of inulin and PAH clearance were tested in 25 patients with normal and impaired renal function. The clearance calculated from the infusion rate and the serum levels was equal to the classical clearance calculated from serum levels and urinary excretion. The advantages of the clearance method without urine sampling are: a) catheterization of the bladder can be omitted, b) less analytical work and, c) exact timing serum and urine samples is unneccessary.