Master Renal Clearance with Picmonic for Medicine

Renal clearance describes the volume of plasma from which a substance is completely removed by the kidneys in a given time. If 1 liter of plasma contains a substance and the kidneys remove all of it in one hour, the clearance is 1 L/hr. If only half is removed, clearance is 0.5 L/hr.
This value helps determine whether a substance is primarily filtered, reabsorbed, or secreted by the nephron.

Creatinine clearance is a practical clinical tool for estimating glomerular filtration rate (GFR), which reflects overall kidney function.
Creatinine is produced from the muscle metabolism of creatine phosphate and is freely filtered at the glomerulus. It is not reabsorbed and only minimally secreted by renal tubules, making it a close but slightly overestimated measure of true GFR.

Renal clearance (C_x) is equal to the urine concentration of substance X (U_x) multiplied by the urine flow rate (V) divided by the plasma concentration of substance X (P_x).

This represents the amount of substance X in the urine, typically measured in mg/dL or mmol/L.
It reflects how much of the substance was filtered and/or secreted, minus what was reabsorbed.

This represents the volume of urine produced per unit time, usually expressed in mL/min.
For clinical calculations, a 24-hour urine collection is often used to measure both flow rate and urine solute concentration.

This value, obtained from a blood sample, represents the concentration of substance X in the plasma.
Dividing the product of Uₓ and V by Pₓ yields a volume/time unit (e.g., mL/min), showing how much plasma is cleared of that substance in one minute.