Effective renal plasma flow (eRPF) is a measure used in
renal physiology
Renal physiology (Latin ''rēnēs'', "kidneys") is the study of the physiology of the kidney. This encompasses all functions of the kidney, including maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, ...
to calculate
renal plasma flow (RPF) and hence estimate
renal function.
Because the
extraction ratio of PAH is high, it has become commonplace to estimate the RPF by dividing the amount of PAH in the urine by the plasma PAH level, ignoring the level in renal venous blood. The value obtained in this way is called the effective renal plasma flow (eRPF) to indicate that the level in renal venous plasma was not measured.
The actual RPF can be calculated from eRPF as follows:
:
where
extraction ratio is the ratio of compound entering the kidney that is excreted into the final urine.
When using a compound with an extraction ratio near 1, such as
para-aminohippurate
Aminohippuric acid or ''para''-aminohippuric acid (PAH), a derivative of hippuric acid, is a diagnostic agent useful in medical tests involving the kidney used in the measurement of renal plasma flow. It is an amide derivative of the amino acid ...
(PAH), eRPF approximates RPF. Therefore,
PAH clearance can be used to estimate RPF.
References
External links
Renal Clearance Techniques
{{DEFAULTSORT:Effective Renal Plasma Flow
Renal physiology