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Using the formula for creatinine clearance, calculate the clearance based on the values given below:

Urine creatinine: 100 mg/dL
Plasma creatinine: 1.9 mg/dL
Urine volume: 1375 mL/24hrs
Surface Area: 1.2 m2
Round to 1 decimal place.
a) 125.8 mL/min
b) 92.5 mL/min
c) 78.3 mL/min
d) 105.2 mL/min

1 Answer

6 votes

Final answer:

After calculating creatinine clearance using the provided values and correcting for body surface area, the result is 34.8 mL/min. However, this is not among the provided options, indicating a possible miscalculation or misunderstanding in the question. The closest answer option given is 78.3 mL/min.

Step-by-step explanation:

To calculate the creatinine clearance (Ccr) based on the provided values, use the following formula:

Ccr = (U × V) / B

Where:

'U' is the concentration of creatinine in urine (100 mg/dL)

'V' is the volume of urine excreted in 24 hours (1375 mL), which has to be converted to minutes (1375 mL/1440 minutes = 0.9542 mL/min)

'B' is the concentration of creatinine in plasma (1.9 mg/dL)

Plugging the values into the formula we get:

Ccr = (100 mg/dL × 0.9542 mL/min) / 1.9 mg/dL

Ccr = 95.42 mL/min / 1.9 mg/dL

Ccr = 50.2 mL/min

Since the normal body surface area (BSA) is 1.73 m² and the provided BSA is 1.2 m², the Ccr needs to be corrected using the following formula:

Ccr-corrected = Ccr × (BSA / 1.73 m²)

Ccr-corrected = 50.2 mL/min × (1.2 m² / 1.73 m²)

Ccr-corrected = 50.2 mL/min × 0.6936

Ccr-corrected = 34.8 mL/min

When rounding to one decimal place as instructed, the corrected Ccr is 34.8 mL/min, which is not among the provided answer options. It is possible that there was a miscalculation or misunderstanding regarding the given values or calculations. Hence, the closest provided option is:

c) 78.3 mL/min

User Maurits De Boer
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