Magnesium (Mg+) test

      The bulk of magnesium is combined with calcium and phosphorus in the bones, with very small amounts present in the bloodstream . Magnesium is necessary for muscular contraction, carbohydrate metabolism, and protein synthesis . It is usually filtered by the kidney through the glomerulus, and reabsorbed into the bloodstream by the renal tubule. Magnesium levels can be used as an indicator of metabolic activity and renal function. Since
magnesium is present in a variety of foods, a normal diet will maintain the body's magnesium supply.

Normal Range
1.6-3.0 mEq/L

Variations from Normal. An increase in plasma magnesium, hypermagnesemia, is usually caused by renal dysfunction or failure. Other diseases or syndromes associated with increased magnesium levels include hypothyroidism, Addison's disease, and dehydration. Excessive ingestion of magnesium via antacids, such as milk of magnesia, will also cause an increase in plasma magnesium.
Hypomagnesemia, decreased plasma magnesium, is usually due to
some type of chronic dietary or intestinal absorption problem. Diseases such as ulcerative colitis, chronic alcoholism, chronic pancreatitis, and chronic diarrhea will exhibit decreased magnesium levels. Other situations that result in hypomagnesemia include toxemia of pregnancy, hyperthyroidism, hypoparathyroidism,
cirrhosis of the liver, and excessive secretion of the hormone
aldosterone .
Magnesium deficiencies can be corrected by the proper administration of magnesium sulfate . Early symptoms of magnesium deficit include muscle cramps, tremors, and insomnia. It should be noted that decreases in urinary magnesium may be detected before decreases in plasma magnesium.
Low levels of calcium and potassium may mask the presence of hypomagnesemia.

Interfering Circumstances. A variety of medications can interfere with laboratory measurement of magnesium levels. Prolonged treatment involving lithium, magnesium products such as antacids and laxatives, and salicylate products such as aspirin will cause a false increase in plasma magnesium levels. This is particularly possible in the face of renal dysfunction. Administration
of calcium gluconate, which is used to replenish the body's
calcium reserves, can also interfere with testing methods and cause a false result that indicates a decreased magnesium level.