When capillary and interstitial hydrostatic pressures are 30 mm of Hg and 5 mm of Hg and colloid oncotic pressure of capillaries and interstitum if 25 mm of Hg and 5 mm of Hg, what is the Net filtration pressure?

**Core Concept**
The **Net Filtration Pressure (NFP)** is the sum of forces that drive fluid out of the capillaries and into the interstitial space. It is determined by the balance between hydrostatic and oncotic pressures.

**Why the Correct Answer is Right**
To calculate NFP, we use the formula: NFP = (Capillary Hydrostatic Pressure - Interstitial Hydrostatic Pressure) - (Capillary Oncotic Pressure - Interstitial Oncotic Pressure). Plugging in the values: NFP = (30 mmHg - 5 mmHg) - (25 mmHg - 5 mmHg) = 25 mmHg - 20 mmHg = 5 mmHg.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not accurately reflect the calculation based on the given pressures.
**Option B:** Incorrect as it mistakenly suggests a different arithmetic operation or values.
**Option C:** Incorrect because it is not the result of the correct calculation.
**Option D:** Incorrect as it does not match the calculated NFP.

**Clinical Pearl / High-Yield Fact**
Remember, the Net Filtration Pressure is crucial in understanding how fluid moves between the capillaries and interstitium, which is vital for maintaining proper fluid balance and blood pressure.

**Correct Answer:** 5 mmHg

✓ Correct Answer: A. 5 mm Hg