PHSI 208 Lecture Notes - Lecture 4: Renal Function, Inulin, Creatinine
Document Summary
Clearance as a non-invasive way to measure gfr: Clearance of a solute is the rate at which a solute disappears from the body by excretion (through urination) or metabolism. The solutes of a substance that is not reabsorbed are cleared through gfr. For a solute that is cleared only by renal excretion, clearance is expressed as the volume of plasma passing through the kidney that has been totally cleared of that solute in a given period of time (usually a minute). This way we can compare with gfr to see if they are reabsorbed: ex: clearance for urea is 65 ml/min. = 50 ml/min: therefore, the kidneys remove all of solute z in a 50 ml plasma sample in one minute. To most accurately calculate gfr, we need to look at the clearance of a substance that is freely filtered and neither reabsorbed or secreted.
