[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
July 15, 1968

Renal Clearance Studies

Author Affiliations

From the departments of medicine of the Chicago Medical School, University of Health Sciences; Mount Sinai Hospital Medical Center (Dr. Freedman); and Cook County Hospital (Dr. Dunea), Chicago.

JAMA. 1968;205(3):170-171. doi:10.1001/jama.1968.03140290062018

Clearance studies are widely used to assess glomerular filtration rate and renal blood flow and to study the excretion of various substances by the kidney. The renal clearance of a substance represents the virtual or theoretical volume of plasma which is completely cleared of this substance in a given unit of time. It is usually expressed in milliliters per minute and calculated from the formula UV÷P, where U and P represent the urine and plasma concentration and V is the volume of the urine.1-3 Clearances have played an important role in the study of renal physiology and have provided much circumstantial evidence regarding the relative importance of glomerular and tubular excretory mechanisms.

Urea Clearance  Since retention of urea in the blood is accompanied by decreased urinary excretion, students of renal disease in the early 1900's had attempted to evaluate renal function by relating the concentration of urea in urine