Reliable marker for estimating GFR in children is _________
**Core Concept**
Estimating Glomerular Filtration Rate (GFR) in children is crucial for assessing kidney function and monitoring renal health. A reliable marker is essential for accurate diagnosis and treatment planning.
**Why the Correct Answer is Right**
The correct answer is **C. Plasma Creatinine (eGFRcys)**. This method involves measuring the plasma creatinine level, which is a byproduct of muscle metabolism. Creatinine is freely filtered by the glomeruli and reabsorbed by the proximal tubules, making it a reliable marker for estimating GFR in children. The eGFRcys formula takes into account the child's age, sex, and weight to provide an accurate estimate of GFR.
**Why Each Wrong Option is Incorrect**
* **Option A:** Serum urea is not a reliable marker for estimating GFR in children, as it can be affected by various factors such as hydration status, diet, and liver function.
* **Option B:** Blood urea nitrogen (BUN) is also not a reliable marker, as it can be influenced by factors such as protein intake, gastrointestinal bleeding, and certain medications.
**Clinical Pearl / High-Yield Fact**
Remember that eGFRcys is not a substitute for direct measurement of GFR using inulin clearance, but it is a convenient and reliable estimate of GFR in children.
**Correct Answer:** C. Plasma Creatinine (eGFRcys)