The normal serum magnesium level is approximately:

The normal serum magnesium level is approximately:

• A. 0.5 to 1.0 mEq/L
• B. 1.5 to 2.0 mEq/L
• C. 2.5 to 3.0 mEq/L
• D. 3.5 to 4.0 mEq/L

Answer: (B)

Magnesium in the blood is kept within a tight range, and the normal serum level is about 1.5 to 2.0 mEq/L. This range reflects how the body balances intestinal absorption, renal excretion, and intracellular distribution. Magnesium is essential for many processes, including stabilizing neuromuscular transmission and supporting cardiac conduction. Values below this range—hypomagnesemia—can cause increased neuromuscular excitability and arrhythmias, and in the surgical setting may make responses to neuromuscular blockers unpredictable. Values above this range—mild to moderate hypermagnesemia—can lead to diminished reflexes, hypotension, bradycardia, and potentially more serious cardiac effects. The other options describe levels that are either too low or too high compared with the normal serum magnesium range, making the 1.5 to 2.0 mEq/L range the correct description of normal.

Magnesium in the blood is kept within a tight range, and the normal serum level is about 1.5 to 2.0 mEq/L. This range reflects how the body balances intestinal absorption, renal excretion, and intracellular distribution. Magnesium is essential for many processes, including stabilizing neuromuscular transmission and supporting cardiac conduction. Values below this range—hypomagnesemia—can cause increased neuromuscular excitability and arrhythmias, and in the surgical setting may make responses to neuromuscular blockers unpredictable. Values above this range—mild to moderate hypermagnesemia—can lead to diminished reflexes, hypotension, bradycardia, and potentially more serious cardiac effects. The other options describe levels that are either too low or too high compared with the normal serum magnesium range, making the 1.5 to 2.0 mEq/L range the correct description of normal.