What does renal plasma flow measure?

What does renal plasma flow measure?

• A. Rate of urine production.
• B. Blood flow through the kidneys; used with GFR to assess kidney function.
• C. Filtration fraction.
• D. Efferent arteriole resistance.

Answer: (B)

Renal plasma flow measures the rate at which plasma is delivered to the kidneys—the plasma component of renal blood flow. It reflects kidney perfusion and, together with GFR, helps assess overall kidney function (for example, the filtration fraction is GFR divided by RPF). PAH clearance is typically used to estimate RPF because PAH is almost completely removed from plasma in a single pass through the kidney. This concept is distinct from urine production, which depends on filtration plus reabsorption and secretion along the tubules, and from filtration fraction or efferent arteriole resistance, which describe other aspects of renal physiology.

Renal plasma flow measures the rate at which plasma is delivered to the kidneys—the plasma component of renal blood flow. It reflects kidney perfusion and, together with GFR, helps assess overall kidney function (for example, the filtration fraction is GFR divided by RPF). PAH clearance is typically used to estimate RPF because PAH is almost completely removed from plasma in a single pass through the kidney. This concept is distinct from urine production, which depends on filtration plus reabsorption and secretion along the tubules, and from filtration fraction or efferent arteriole resistance, which describe other aspects of renal physiology.