In this context, the terms are commonly given subscripts to refer to arterial or venous blood or plasma flow, as in RBFa, RBFv, RPFa, and RPFv.
In practice, PAH clearance is used instead to calculate the effective renal plasma flow (eRPF).
In this way PAH, at low doses, is almost completely cleared from the blood during a single pass through the kidney.
Finally, renal blood flow (RBF) can be calculated from a patient's renal plasma flow (RPF) and hematocrit (Hct) using the following equation: If the kidney is methodologically perfused at moderate pressures (90–220 mm Hg performed on an experimental animal; in this case, a dog), then, there is a proportionate increase of: Along with the increase in pressure.
At low perfusion pressures, Angiotensin II may act by constricting the efferent arterioles, thus mainlining the GFR and playing a role in autoregulation of renal blood flow.