Question

You are performing an inulin clearance test on a patient in order to determine their GFR. Inulin is being infused such that blood plasma concentration is 0.5 mg/mL. The patient produces urine that has an inulin concentration of 40 mg/mL at a rate of 1.5 mL/min. What is this patient's GFR in mL/min?

Answer 1

To calculate the Glomerular Filtration Rate (GFR) using an inulin clearance test, apply the formula GFR = (U x V) / P. With the inulin concentration in urine (U) as 40 mg/mL, urine flow rate (V) as 1.5 mL/min, and plasma concentration (P) as 0.5 mg/mL, the patient's GFR is calculated to be 120 mL/min.

Step-by-step explanation:

The question asks us to calculate the Glomerular Filtration Rate (GFR) using the inulin clearance test. To determine the GFR, we use the following formula:

GFR = (U x V) / P

Where:

• U is the concentration of inulin in the urine (40 mg/mL)
• V is the urine flow rate (1.5 mL/min)
• P is the concentration of inulin in the plasma (0.5 mg/mL)

Substituting the given values:

GFR = (U x V) / P = (40 mg/mL x 1.5 mL/min) / 0.5 mg/mL

Calculating this gives:

GFR = (60 mg/min) / 0.5 mg/mL = 120 mL/min

Therefore, the patient's GFR is 120 mL/min.