Magnesium (Mg), Total Serum Blood Test

A magnesium test is used to measure the level of magnesium in the blood (or sometimes urine). Abnormal levels of magnesium are most frequently seen in conditions or diseases that cause impaired or excessive excretion of magnesium by the kidneys or that cause impaired absorption in the intestines.

The normal range for blood magnesium level is 1.7 to 2.2 mg/dL (0.85 to 1.10 mmol/L). Normal value ranges may vary slightly among different laboratories.

Magnesium deficiency, also known as hypomagnesemia, is an often overlooked health problem. One of the first signs of magnesium deficiency is often fatigue. You may notice muscle spasms, weakness, or stiffness as well. Loss of appetite and nausea are other common symptoms in the early stages. However, you may not notice any symptoms at all in the beginning.

High magnesium levels (between 7 and 12 mg/dL) can impact the heart and lungs, and levels in the upper end of this range may cause extreme fatigue and low blood pressure. Too high levels (above 12 mg/dL) can lead to muscle paralysis and hyperventilation. When levels are above 15.6 mg/dL, the condition may result in a coma.