Renal clearance

Renal clearance describes the volume of plasma completely cleared of a substance by the kidneys per unit time. A higher renal clearance suggests the substance may be cleared almost completely in one pass through the kidneys while a low value describes a substance that may not be eliminated by the kidneys at all. Typically this is calculated by multiplying the volume of urine by the concentration of a substance in the urine, divided by the concentration of the substance in plasma (mg/mL).