It is the volume of the plasma or the blood completely cleared from the drug per unit time by the organ. It has units of volume/time.

The organ clearance cannot exceed the total body clearance. However it can be equal to the total body clearance when the drug is excreted completely by that particular organ.

The organ clearance can be determined from the organ blood flow and its extraction ratio ( CL_{organ = Qorgan . E).}

The organ clearance can be determined from the excretion rate over a short interval and the average plasma concentration during this interval. (CL_organ= Drug excretion rate by the organ/Cp_average).

The extraction ratio is the fraction of the drug presented to the organ which is eliminated during a single pass through the organ.

The extraction ratio can have values between 0 and 1 (or 0% - 100%). It is zero when the drug is not eliminated by the organ, and it is 1 when all the drug presented to the organ is eliminated during a single pass.

The extraction ratio does not have units.