Magnesium (Serum)

Serum Magnesium measures the small fraction (<1%) of total body magnesium circulating in the blood. While readily available, it may not accurately reflect intracellular stores (see RBC Magnesium). Magnesium is a critical cofactor for over 600 enzymes involved in energy production, nerve/muscle function, blood pressure, glucose control, bone health, and DNA/RNA synthesis. Low serum levels (hypomagnesemia) can cause weakness, cramps, and arrhythmias, but intracellular deficiency can exist even with normal serum levels.