Question

Twenty-four hour urine sample: Total volume = 1350 ml

Inulin concentration = 1.86 mg/ml, Creatinine concentration = 3.6 mg/ml

Sodium concentration = 0.17 mEq/ml, Urea concentration = 24.0 mg/ml

Potassium concentration = 0.12 mEq/ml, PAH concentration = 10 mg/ml

Plasma sample taken at the midpoint during urine collection: Hematocrit = 43%

Inulin concentration = 0.013 mg/ml, Creatinine concentration = 0.019 mg/ml

Sodium concentration = 0.13 mEq/ml, Urea concentration = 0.28 mg/ml

Potassium concentration = 0.008 mEq/ml, PAH concentration = 0.014 mg/ml

What is RPF exp (renal plasma flow experimental) ml/min?

When I worked it out, I got 793.65 ml/min. Is this correct?

Answer 1

I think your answer a bit off.
Go through the following calculations and let me know what happened.

osma actor diny ts the gven doto Urine flow YaleニーTotal volume -1350-mu /rin 24 x(0)mins 4X 0 01L m 13500 -n시min 0 01L X24 X60 .. . ERPF= 663.64 n11min RF ERfF

Hence, RPF = 744.04 ml/min

Note: Here Renal plasma flow is written as ERPS/0.9
This is because the formula for ERPF ignores the 10% PAH which is not secreted (i.e. 10% remains in renal vein). Only 90% of PAH is secreted through tubules and hence to calculate the true RPF we have to correct the ERPF by dividing it by 0.9 (Fractional form of 90%).