What are the various tests that can be used to monitor magnesium levels and what are the pros and cons?

The entry-level test to evaluate magnesium status is the serum magnesium concentration which indicates hypomagnesemia or hypermagnesemia. However, the magnesium in serum represents only 0.3% of the total body magnesium stores and may not be in equilibrium with the major stores of magnesium such as bone and soft tissue.

A 24-hour urine specimen for magnesium excretion is helpful to identify if the kidneys tend to waste magnesium. The magnesium load test, where magnesium is given intravenously, is considered to be the best test to evaluate a total body magnesium deficit. Further, magnesium has been measured in red blood cells, white blood cells, hair and soft tissue but these tests may be difficult and timely to perform and are not offered by routine clinical laboratories.

A few common signs of magnesium deficiency include leg cramps, migraines, and fatigue. Not all patients experience the signs and symptoms of magnesium deficiency. Because blood tests are not always accurate, it is recommended to proactively supplement your patients at risk for magnesium deficiency.

Dosing: Two tablets of Mag-Ox 400 per day with food as a dietary supplement for magnesium deficiency.

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