What is the electrolyte content of normal saline (0.9% sodium chloride)?

What is the electrolyte content of normal saline (0.9% sodium chloride)?

• A. Sodium 130 mEq/L and chloride 109 mEq/L
• B. Sodium 77 mEq/L and chloride 77 mEq/L
• C. Sodium 154 mEq/L and chloride 154 mEq/L
• D. Sodium 154 mEq/L and potassium 4 mEq/L

Answer: (D)

Normal saline is isotonic with extracellular fluid and has identical concentrations of the two main ions: sodium and chloride, each at 154 mEq/L. It contains no potassium. This composition is what defines 0.9% NaCl and explains its use for rapid intravascular volume expansion without altering potassium levels. The other option sets misstate either the sodium or chloride values or introduce potassium, which is not a component of normal saline.

Normal saline is isotonic with extracellular fluid and has identical concentrations of the two main ions: sodium and chloride, each at 154 mEq/L. It contains no potassium. This composition is what defines 0.9% NaCl and explains its use for rapid intravascular volume expansion without altering potassium levels. The other option sets misstate either the sodium or chloride values or introduce potassium, which is not a component of normal saline.