If the GFR is 125 mL/min and the renal plasma flow is 700 mL/min, the filtration fraction is

Options

A. About 6%
B. About 18%
C. About 12%
D. About 24%

Answer

To find the filtration fraction (FF), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **GFR (Glomerular Filtration Rate)**: The amount of filtrate formed by the kidneys per minute. In this case, GFR = 125 mL/min.
- **RPF (Renal Plasma Flow)**: The amount of blood plasma delivered to the kidneys per minute. In this case, RPF = 700 mL/min.

2. **Formula for Filtration Fraction**:
- The filtration fraction (FF) can be calculated using the formula:
\[ \text{FF} = \frac{\text{GFR}}{\text{RPF}} \]

3. **Substitute the Values**:
- Substitute the given values into the formula:
\[ \text{FF} = \frac{125 \, \text{mL/min}}{700 \, \text{mL/min}} \]

4. **Calculate the Filtration Fraction**:
- Perform the division:
\[ \text{FF} = \frac{125}{700} \approx 0.17857 \]

5. **Convert to Percentage**:
- To express the filtration fraction as a percentage, multiply by 100:
\[ \text{FF} \approx 0.17857 \times 100 \approx 17.857 \% \]

6. **Round the Answer**:
- Rounding to one decimal place gives us:
\[ \text{FF} \approx 18\% \]

### Final Answer:
The filtration fraction is approximately **18%**.

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