Renal Formulas

1. Renal Clearance: Cx = Ux V / Px
• Cx: clearance of  X (mL/min)
• Ux: urine concentration of X
• V: urine flow rate
• Px: plasma concentration of X
2. Renal Blood Flow: RBF = RPF / (1-Hct)
• RPF: renal plasma flow
3. (Efective) Renal Plasma Flow: ERPF = RPF = Cpah
• pah: para-amino-hippurate
• Note: plasma = blood - RBC's
• RPF: how much plasma is filtered per minute
4. Glomerular Filtration Rate: GFR = Ci = Ui xV / Pi
• Ci: clearance of inulin
• Ui: urine concentration of inulin
• V: urine flow rate
• Pi: plasma concentration of inulin
• GFR: how much blood is filtered per minute (N: 90-120 mL/min)
• GFR = Creatinine Clearance
5. Filtration Fraction: FF = GFR / RPF (N: 20%)
6. Filtered Load = GFR X Px
7. Excretion Rate = V X Ux