Normal Plasma Sodium Levels Explained

Sodium (Na+) is a crucial electrolyte found in the blood plasma, playing a vital role in maintaining fluid balance, nerve impulse transmission, and muscle function. Monitoring the concentration of sodium in the plasma is important for assessing overall health.

Understanding the Correct Sodium Range

The question asks for the normal levels of sodium in plasma. Based on standard medical reference ranges:

• The normal concentration of sodium in human plasma typically falls between 135 and 143 milliequivalents per liter (mEq/L).

This range ensures proper physiological functions are maintained. Option 1 correctly identifies this standard range.

Why Other Ranges Are Incorrect

Let's examine why the other options provided are not the standard normal range for plasma sodium:

• Option 2: 97-106 mEq/L - This range is significantly lower than the established normal levels for plasma sodium. Levels this low would indicate severe hyponatremia (low blood sodium).
• Option 3: 90-196 mg/100 ml - This option uses different units (mg/100 ml) and presents a very wide range that is not specific to plasma sodium. While sodium can be measured in mg/dL, the standard clinical unit is mEq/L, and this range is physiologically improbable for normal sodium levels.
• Option 4: 60-100 mg/dl - Similar to option 3, this uses different units (mg/dl) and represents levels that are too low for normal plasma sodium concentration. This range might be more applicable to other substances, like blood glucose.

Therefore, the most accurate and widely accepted normal range for sodium in plasma is 135-143 mEq/L.