Advanced Patient Assessment Practice Exam

Which of the following values represents a normal serum sodium level?

1. 135 - 145 mEq/L

2. 7 - 20 mEq/L

3. 3.5 - 5.0 mEq/L

4. 98 - 105 mEq/L

The correct answer is: 135 - 145 mEq/L

The normal serum sodium level falls within the range of 135 to 145 mEq/L. This range is crucial for maintaining fluid balance, nerve function, and muscle contraction in the body. Sodium is the primary cation in extracellular fluid, and its concentration is tightly regulated by various homeostatic mechanisms, including hormone action (such as aldosterone) and renal function. Understanding this range is essential for health professionals, as deviations from normal serum sodium levels can indicate conditions such as hyponatremia (low sodium) or hypernatremia (high sodium), both of which can lead to serious complications like neurological disturbances, fluid overload, or dehydration. In contrast, the other options represent normal values for different electrolytes or substances in the body. The second option represents the range for blood urea nitrogen levels, the third option represents normal potassium levels, and the fourth option refers to normal serum osmolality. These other values illustrate the range for different components of the body's chemistry, highlighting the importance of understanding the specific context of each electrolyte or substance being evaluated.